Αν συνεχίσω να φτερνίζομαι έτσι, θα ξαναπάω στον φαρμακοποιό αύριο.

Αν means if and introduces the condition.

This sentence follows a very common Greek pattern:

• αν + subjunctive-type verb form = the if clause
• θα + verb = the result clause

So:

• Αν συνεχίσω... = If I continue / If I keep...
• θα ξαναπάω... = I’ll go again...

Greek does not usually use θα in the αν clause here.

Because after αν in a future, real possibility like this, Greek normally uses the subjunctive form, not the plain present indicative.

So:

• αν συνεχίσω = if I continue / if I do keep on
• not normally αν συνεχίζω for this meaning

More technically, συνεχίσω is the perfective subjunctive form of συνεχίζω.

English says if I continue, using what looks like an ordinary present. Greek uses a different structure.

Because συνεχίζω commonly takes να + verb to mean continue to do something.

So:

• συνεχίζω να διαβάζω = I continue to read / I keep reading
• συνεχίσω να φτερνίζομαι = I continue to sneeze / I keep sneezing

Here να introduces the action that is being continued.

Because φτερνίζομαι shows an ongoing or repeated action, which fits keep sneezing.

Compare:

• να φτερνίζομαι = to be sneezing / to keep sneezing / to sneeze repeatedly
• να φτερνίσω = to sneeze once / as a single event

Since the idea is If I keep sneezing like this..., the imperfective form φτερνίζομαι is the natural choice.

No. It has an active meaning even though it uses a middle/passive-looking ending.

So φτερνίζομαι simply means:

• I sneeze

This is something learners meet a lot in Greek: some verbs have -ομαι forms but are not actually passive in meaning.

Here έτσι means something like:

• like this
• in this way
• at this rate

In this sentence, it means the speaker is sneezing in a worrying or noticeable way:

• Αν συνεχίσω να φτερνίζομαι έτσι...
• If I keep sneezing like this...

So it is not just a literal thus; it often has a natural conversational sense like if this keeps up.

ξαναπάω means go again or go back.

It is made from:

• ξανα- = again
• πάω = I go

So:

• θα ξαναπάω = I’ll go again / I’ll go back

Greek very often puts ξανα- directly onto the verb. You could also hear:

• θα πάω ξανά

but θα ξαναπάω is very natural and common.

Στον is a contraction of:

• σε + τον → στον

It means to the or sometimes at the, depending on context.

Here it means to the:

• στον φαρμακοποιό = to the pharmacist

This happens all the time in Greek:

• σε + το → στο
• σε + τη(ν) → στη(ν)
• σε + τον → στον

Because φαρμακοποιός means pharmacist (the person), while φαρμακείο means pharmacy (the place).

So:

• πάω στον φαρμακοποιό = I go to the pharmacist
• πάω στο φαρμακείο = I go to the pharmacy

In real life, both can make sense, but they are not identical. This sentence focuses on the person.

Θα is the standard particle used to form the future in Modern Greek.

So:

• πάω = I go / I am going
• θα πάω = I will go
• θα ξαναπάω = I will go again / I will go back

This is the normal way to make the future.

Yes, it can go elsewhere. Greek word order is fairly flexible.

All of these are possible, with slightly different emphasis:

• Αν συνεχίσω να φτερνίζομαι έτσι, θα ξαναπάω στον φαρμακοποιό αύριο.
• Αύριο θα ξαναπάω στον φαρμακοποιό, αν συνεχίσω να φτερνίζομαι έτσι.
• Αν συνεχίσω να φτερνίζομαι έτσι, αύριο θα ξαναπάω στον φαρμακοποιό.

Putting αύριο at the end is a very natural, neutral choice.

Because the sentence begins with the if clause:

• Αν συνεχίσω να φτερνίζομαι έτσι,
• then the main clause:
• θα ξαναπάω στον φαρμακοποιό αύριο.

This comma works much like English punctuation in sentences such as:

• If I keep sneezing like this, I’ll go back to the pharmacist tomorrow.

In speech, there is usually a small pause there too.