Όταν αργεί πολύ το λεωφορείο, γίνομαι ανήσυχος αλλά προσπαθώ να μην πανικοβάλλομαι.

Here it has a habitual sense, so when and whenever are both good ways to understand it.

Because the sentence is describing something that happens generally or repeatedly, the meaning is:

Whenever the bus is very late, I get anxious, but I try not to panic.

So όταν is not just about one single occasion here.

Greek word order is more flexible than English word order.

So both of these are possible:

• Όταν αργεί πολύ το λεωφορείο
• Όταν το λεωφορείο αργεί πολύ

They mean the same thing. The version in your sentence sounds natural and can put a little more focus on the idea of being late before naming the subject.

In English, this kind of movement is much more limited, but in Greek it is very common.

The verb αργώ often means to be late.

So αργεί πολύ το λεωφορείο means:

• the bus is very late
• or more literally, the bus is late by a lot

The word πολύ here strengthens the idea. It is not saying the bus is simply late, but quite late / very late.

Because γίνομαι means I become / I get, while είμαι means I am.

So:

• γίνομαι ανήσυχος = I become anxious / I get worried
• είμαι ανήσυχος = I am anxious / I am worried

In this sentence, the speaker is talking about a change of state: the bus is late, and then the speaker starts feeling anxious. That is why γίνομαι fits well.

Because it agrees with the speaker.

Greek adjectives change form depending on gender and number. Since the verb γίνομαι means I become, the adjective describes the speaker, and in this sentence the speaker is understood as masculine singular:

• ανήσυχος = masculine
• ανήσυχη = feminine

So a female speaker would say:

γίνομαι ανήσυχη

Because Greek often leaves out subject pronouns when they are already clear from the verb ending.

For example:

• γίνομαι = I become
• προσπαθώ = I try

So Greek does not need εγώ here. If you added εγώ, it would usually sound more emphatic, like:

I get anxious, but I try not to panic.

After προσπαθώ (I try), Greek normally uses να followed by a verb.

So:

• προσπαθώ να μην πανικοβάλλομαι = I try not to panic

This is one of the biggest differences from English. English often uses an infinitive:

• I try not to panic

But Modern Greek does not use an infinitive this way. Instead, it uses να + a finite verb form.

Because μην is the negative used with να-clauses and other non-indicative constructions.

So:

• δεν negates ordinary statements
• μην negates να clauses

That is why Greek says:

• προσπαθώ να μην πανικοβάλλομαι

and not:

• προσπαθώ να δεν πανικοβάλλομαι ❌

This is a very important pattern to learn: να + verb → if negative, use μην.

Because πανικοβάλλομαι is the usual form meaning I panic / I get panicked.

Even though it looks like a middle/passive form because it ends in -ομαι, its meaning here is active in English.

Compare:

• πανικοβάλλομαι = I panic
• πανικοβάλλω κάποιον = I cause someone to panic

So the sentence uses the correct form for the speaker’s own reaction.

Yes. ανησυχώ is also very natural and means I worry / I get worried.

For example:

Όταν αργεί πολύ το λεωφορείο, ανησυχώ...

The difference is mostly one of nuance:

• ανησυχώ = I worry / I feel worried
• γίνομαι ανήσυχος = I become anxious / I get uneasy

The version in your sentence slightly emphasizes the shift into that emotional state.

Because the sentence describes a general repeated situation, not one single event.

So Greek uses the present:

• αργεί = is late
• γίνομαι = I become
• προσπαθώ = I try
• πανικοβάλλομαι = I panic

This gives the meaning of something that happens whenever this situation occurs. It is similar to English sentences like:

• When the bus is late, I get anxious.
• If that happens, I try not to panic.