Learn Hardcore German: Wenn ich mich einsam fühle, rufe ich meine Freundin an. - When I feel lonely, I call my girlfriend.

Wenn is a subordinating conjunction (a Nebensatz-Einleiter). In German, subordinating conjunctions send the conjugated verb to the end of the clause.

So:

Wenn ich mich einsam fühle
– fühle is the conjugated verb, so it goes to the end.

In the main clause, the verb is in second position:

rufe ich meine Freundin an – rufe is the conjugated verb, and it’s in position 2.

So the sentence structure is:

[Wenn‑clause with verb at the end], [main clause with verb in 2nd position].

Why do we say „ich fühle mich“ and not just „ich fühle“?

With the meaning “to feel (a certain way)”, fühlen is usually reflexive in German:

Ich fühle mich einsam. – I feel lonely.
Ich fühle mich müde. – I feel tired.

The reflexive pronoun (mich, dich, sich …) refers back to the subject and is required in this meaning.

Without the reflexive pronoun, fühlen usually means “to touch/feel something with your hands”:

Ich fühle den Stoff. – I feel the fabric.

So „Wenn ich einsam fühle“ is ungrammatical; it needs mich:

✅ Wenn ich mich einsam fühle …

Why is it „mich“ and not „mir“?

Reflexive pronouns in German have accusative and dative forms.

With fühlen in the sense of “to feel (an emotion/condition)”, you use the accusative:

ich fühle mich
du fühlst dich
er/sie/es fühlt sich
wir fühlen uns
ihr fühlt euch
sie fühlen sich

You normally get dative reflexive when there is another direct object:

Ich wasche mich. – I wash myself. (accusative)
Ich wasche mir die Hände. – I wash my hands. (mir = dative; Hände = direct object)

Since there is no other direct object with fühlen, we use mich (accusative), not mir.

Could I also say „Wenn ich einsam bin“ instead of „Wenn ich mich einsam fühle“?

Yes, you can, and both are correct, but there is a slight nuance:

Wenn ich einsam bin … – focuses more on the state: when I am lonely.
Wenn ich mich einsam fühle … – focuses a bit more on the subjective feeling: when I feel lonely.

In many everyday contexts, they are interchangeable and both sound natural. Your original version with fühlen is very idiomatic.

What’s the difference between „einsam“ and „allein“?

Roughly:

einsam = lonely (emotional)
allein = alone (physically, can be neutral or even positive)

Examples:

Ich bin allein, aber nicht einsam.
I’m alone, but not lonely.
Ich fühle mich einsam, obwohl viele Leute da sind.
I feel lonely although many people are there.

In your sentence, einsam is correct because it describes the emotional feeling, not just being physically by yourself.

Why is it „meine Freundin“ and not „meiner Freundin“?

Because meine Freundin here is the direct object (accusative case) of anrufen:

jemanden anrufen – to call somebody (on the phone).

Cases:

Nominative (subject):
Meine Freundin ruft mich an. – My (female) friend calls me.
Accusative (direct object):
Ich rufe meine Freundin an. – I call my (female) friend.

So in your sentence, meine Freundin is accusative, and that form is meine, not meiner.

Why is it „rufe ich meine Freundin an“ and not „ich rufe meine Freundin“ or „ich rufe an meine Freundin“?

Anrufen is a separable verb:

infinitive: anrufen
conjugated: ich rufe … an

The prefix „an“ splits off and goes to the end of the clause:

Ich rufe meine Freundin an.

You cannot say:

❌ ich rufe meine Freundin (that just means “I call my girlfriend”, but in German phone calling specifically needs anrufen)
❌ ich rufe an meine Freundin (this sounds like treating an as a preposition, which is wrong here)

So the correct pattern is:

jemanden anrufen → Ich rufe meine Freundin an.

Does „Freundin“ mean “friend” or “girlfriend”?

It can mean either, depending on context:

Freundin = female friend or girlfriend
Freund = male friend or boyfriend

Spoken German usually relies on context and intonation. In writing, people sometimes clarify:

eine gute Freundin – a good (female) friend
meine feste Freundin / meine Freundin (im Sinne von Partnerin) – my girlfriend (as a romantic partner)

In your sentence, meine Freundin could be understood either way; more context would clarify.

Can I change the order and say „Ich rufe meine Freundin an, wenn ich mich einsam fühle“?

Yes. Both orders are correct and mean the same thing:

Wenn ich mich einsam fühle, rufe ich meine Freundin an.
Ich rufe meine Freundin an, wenn ich mich einsam fühle.

Rule:

Subordinate clause (wenn … fühle) + comma + main clause (rufe ich … an),
or
Main clause + comma + subordinate clause.

Only the comma and verb positions must follow the rules; the overall meaning is unchanged.

What is the difference between „wenn“, „wann“, and „falls“? Why is only „wenn“ correct here?

Short overview:

wenn
– “when(ever)” or “if” (for conditions or repeated situations)
– introduces a subordinate clause
- Wenn ich müde bin, gehe ich schlafen.
wann
– “when?” (a question word about time)
- Wann kommst du? – When are you coming?
  – In indirect questions:
  Ich weiß nicht, wann er kommt.
falls
– “in case / if” (often more hypothetical)
- Falls du Hilfe brauchst, ruf mich an.

In your sentence you talk about a condition / repeated situation (“whenever/if I feel lonely …”), so you need wenn:

✅ Wenn ich mich einsam fühle, rufe ich meine Freundin an.
❌ Wann ich mich einsam fühle, … (ungrammatical here)
Falls ich mich einsam fühle, rufe ich meine Freundin an. – This sounds more like a hypothetical future possibility, not a regular habit.

Why is there a comma after „fühle“?

Because in German you must separate a subordinate clause and a main clause with a comma.

Your sentence has:

Subordinate clause: Wenn ich mich einsam fühle
Main clause: rufe ich meine Freundin an.

Rule:
[Subordinate clause], [main clause].

So the comma after fühle is required.

Can I use the present tense here even if I mean the future, like “when I feel lonely (later), I will call her”?

Yes. German often uses the present tense where English uses “will”.

Wenn ich mich einsam fühle, rufe ich meine Freundin an.
can mean:
- When(ever) I feel lonely, I (habitually) call my girlfriend.
- When I feel lonely (in the future), I will call my girlfriend.

You don’t have to say „werde anrufen“ here. The simple present is the most natural choice.