Posle posla se ne osećam dobro, ali moram malo da se odmaram.

Because posle requires the genitive case.

• Base form: posao = work, job
• After posle = after, it changes to posla

So:

• posao = nominative
• posla = genitive

That is why Posle posla means after work.

Because both osećati se and odmarati se are reflexive verbs in Serbian.

• osećati se = to feel
• odmarati se = to rest

Here, se is not translating a separate English word like myself. It is simply part of how these verbs are normally used.

So:

• ne osećam dobro would sound wrong for I don’t feel well
• odmaram without se usually means I am resting something / giving rest in a different sense, not I am resting myself

This is because se is a clitic, and Serbian clitics usually go in the second position of the clause.

In:

Posle posla se ne osećam dobro

the whole phrase Posle posla comes first, so se goes right after that phrase.

This word order is very normal in Serbian. You will often see clitics like se, sam, je, ga, mi placed near the beginning of the clause rather than directly next to the word they belong to in English.

They are related, but not the same.

• osećam = I feel / sense something
  For example: Osećam bol = I feel pain
• osećam se = I feel / I am feeling in some condition
  For example: Osećam se dobro = I feel well

So in this sentence, osećam se is the correct form because the speaker is describing their physical state.

Because dobro here is an adverb, not an adjective.

After osećati se, Serbian very often uses adverbs like:

• dobro = well
• loše = badly / poorly
• sjajno = great

So:

• Osećam se dobro = I feel well
• Osećam se loše = I feel bad / unwell

English often uses an adjective in this kind of sentence, but Serbian commonly uses the adverb.

In Serbian, after verbs like morati, it is very common to use da + present tense.

So:

• moram da idem = I have to go
• moram da učim = I have to study
• moram da se odmaram = I have to rest

This is one of the most basic and frequent Serbian patterns. Even though Serbian has infinitives, the da + present construction is extremely common and often the most natural choice.

Malo means a little, for a bit, or a little while.

In this sentence, it softens the statement:

• Moram da se odmaram = I have to rest
• Moram malo da se odmaram = I have to rest a little / for a bit

It makes the sentence sound more natural and less absolute.

It is understandable, but many native speakers would more naturally say:

Moram malo da se odmorim.

Why? Because odmarati se is imperfective, while odmoriti se is perfective.

• odmarati se = to be resting / to rest regularly or over a period of time
• odmoriti se = to get some rest, to rest and complete that action

If the speaker means I need to rest a bit now, then da se odmorim often sounds more idiomatic.

So:

• moram malo da se odmaram = I need to be resting a bit / I need to spend some time resting
• moram malo da se odmorim = I need to rest a bit

The version in the sentence is not impossible, but odmorim is often the more natural everyday choice in this context.

Odmaram comes from odmarati se, which is imperfective.

Serbian verbs usually come in aspect pairs:

• odmarati se = imperfective
• odmoriti se = perfective

Aspect matters because it changes how the action is viewed:

• imperfective = ongoing, repeated, habitual, or uncompleted
• perfective = completed as a whole

That is why:

• moram da se odmaram suggests ongoing or repeated resting
• moram da se odmorim suggests one complete act of resting

English does not mark this as strongly, so this is a very common point of confusion for learners.

Because ne goes with the verb, but se is a clitic with its own placement rules.

So in:

Posle posla se ne osećam dobro

• se occupies the clitic position near the start of the clause
• ne stands directly before the verb osećam

That is why the order is:

• se ne osećam

and not:

• ne se osećam

This is normal Serbian word order.

Yes:

• Posle = after
• posla = work, job (genitive of posao)
• se = reflexive particle
• ne = not
• osećam = I feel
• dobro = well
• ali = but
• moram = I must / I have to
• malo = a little / for a bit
• da = that / to, introducing the verb clause here
• se = reflexive particle
• odmaram = I rest / I am resting

So grammatically, the sentence is built from two clauses:

1. Posle posla se ne osećam dobro
2. ali moram malo da se odmaram

That structure is very typical in Serbian.