Ne brinu me toliko režije koliko mogućnost da opet ostanemo bez grijanja.

It creates a comparison of degree:

• Ne brinu me toliko režije koliko mogućnost...
• literally: The bills don't worry me as much as the possibility...
• natural English: It's not the bills/utilities that worry me so much as the possibility...

So the speaker is saying that both things are worrying, but the second one is more worrying.

Because Croatian uses two different patterns here:

• brinuti nekoga = to worry someone
• brinuti se = to worry / be worried

In this sentence, the meaning is something worries me, so Croatian uses the first pattern:

• režije brinu me
• mogućnost brine me

So me is the person affected, not the subject.

If you said brinem se, that would mean I am worried, which is a different structure.

Me is the accusative form of ja.

It is used because brinuti here is a transitive verb: the thing causing worry is the subject, and the worried person is the direct object.

So the logic is:

• režije = subject
• mogućnost = subject
• me = direct object

In other words, the sentence is built like X worries me, not I worry about X.

Because režije is plural, and it is the first compared item in the structure.

A useful way to read the sentence is:

• Ne brinu me toliko režije koliko mogućnost...
• It's not so much the utilities that worry me as the possibility...

Even though mogućnost is singular, the verb agrees naturally here with the first contrasted noun phrase, režije, which is plural.

So:

• režije → plural
• therefore brinu

Režije usually means household utility costs / bills / running expenses.

Depending on context, it can include things like:

• electricity
• water
• gas
• heating
• building fees
• other regular household charges

It is very often used in the plural, and in this sentence utility bills or household expenses is a good translation.

Because mogućnost is followed by a clause that explains what the possibility is.

So:

• mogućnost da opet ostanemo bez grijanja
• the possibility that we end up without heating again

This da + verb pattern is very common in Croatian after nouns like:

• mogućnost = possibility
• nada = hope
• strah = fear
• želja = wish

It often corresponds to English that... or sometimes an infinitive-like structure, but Croatian naturally prefers da + finite verb here.

Ostanemo is from ostati, which is perfective.

Here that makes sense because the speaker is talking about a single possible event:

• da opet ostanemo bez grijanja
• that we might end up without heating again

If you used ostajemo instead, it would sound more like an ongoing or repeated state/process, which is not the main idea here.

So:

• ostanemo = a possible complete event
• ostajemo = ongoing/habitual remaining

After da, the present tense of a perfective verb often refers to a future or potential event, not to the present moment.

Bez means without, and it requires the genitive case.

So:

• nominative: grijanje = heating
• genitive: grijanja

That is why the sentence has:

• bez grijanja = without heating

This is a very common pattern in Croatian:

• bez vode = without water
• bez struje = without electricity
• bez problema = without problems

Opet means again.

So the speaker is not just worried about losing heating, but about losing it again — meaning it has probably happened before.

It modifies the clause:

• da opet ostanemo bez grijanja
• that we end up without heating again

Its position before the verb is very natural and neutral.

Yes, Croatian word order is flexible, but the original order is natural because it highlights the comparison.

The sentence starts with:

• Ne brinu me toliko režije...

This sets up the first item in the contrast, and then:

• ...koliko mogućnost da opet ostanemo bez grijanja

gives the stronger, more important second item.

A different wording is possible, but the original sounds very natural and expressive. Croatian often uses word order to show focus and emphasis, not just grammar.

In this kind of sentence, toliko helps express degree very clearly.

• ne toliko X koliko Y = not so much X as Y

Without toliko, the sentence would feel less balanced and less idiomatic in this exact comparison pattern.

So while Croatian sometimes allows shorter variants in other contexts, here toliko ... koliko ... is the standard and very natural pair.