Не волнуйся, со мной всё в порядке.

Because the verb is волноваться (to worry / to get worried), and its imperative is formed from the present-tense stem:

• я волнуюсь
• ты волнуешься
• imperative: волнуйся

So:

• Не волнуйся = Don’t worry (to one person, informal)

Russian imperatives are not always built by simply removing -ться and adding something predictable, so this is a form worth memorizing.

-ся is the reflexive ending. In many verbs, it adds a sense like oneself, but in practice it often just forms a standard dictionary verb that must be learned as a whole.

Here, волноваться means to worry / be anxious.

Compare:

• волновать = to worry / trouble someone
  
  • Это меня волнует = That worries me
• волноваться = to worry / be worried
  
  • Я волнуюсь = I’m worried

So in Не волнуйся, the -ся is part of the normal verb form, not something optional.

It is informal singular, used when speaking to:

• one friend
• a child
• a family member
• someone you address with ты

The formal or plural version is:

• Не волнуйтесь

So:

• Не волнуйся = informal Don’t worry
• Не волнуйтесь = formal or plural Don’t worry

Both с and со mean with, but со is often used instead of с when it sounds easier to pronounce.

Russian prefers:

• со мной
• со мной всё в порядке

rather than с мной, which sounds awkward.

This is a common pronunciation-based alternation:

• с братом
• со мной
• со всеми

So со here is not a different meaning—just the natural form before мной.

Мной is the instrumental case of я.

After с / со in the meaning with, Russian normally uses the instrumental:

• я → мной
• ты → тобой
• он → им
• она → ею / ей
• мы → нами

So:

• со мной = with me

In this sentence, со мной всё в порядке literally means something like With me, everything is in order.

Literally, it means something like everything is in order.

Breakdown:

• всё = everything
• в порядке = in order / okay / fine

In natural English, со мной всё в порядке is usually translated as:

• I’m fine
• Everything is okay with me
• I’m all right

This is a very common Russian way to reassure someone.

Russian often says со мной всё в порядке instead of я в порядке.

• со мной всё в порядке sounds very natural and idiomatic
• я в порядке is understandable, but less common in this context and can sound a bit like a direct translation from English

The phrase со мной всё в порядке emphasizes that nothing is wrong with me.

A very similar expression is:

• У меня всё в порядке = Everything is okay with me / Things are fine with me

They are very similar, but the emphasis is a little different.

• Со мной всё в порядке = I’m fine / There’s nothing wrong with me
  • focuses on me personally, often physical or emotional state
• У меня всё в порядке = Everything is fine with me / Things are going well
  • can be broader: life, work, situation, general circumstances

In your sentence, со мной всё в порядке is especially natural after Не волнуйся, because it reassures the listener directly: Don’t worry, I’m okay.

The comma separates two parts of the sentence:

• Не волнуйся = Don’t worry
• со мной всё в порядке = I’m fine

In English, you would often also separate these with a comma:

• Don’t worry, I’m fine.

So the punctuation works similarly here.

Yes. Russian word order is flexible, and the sentence can be rearranged for emphasis.

For example:

• Не волнуйся, со мной всё в порядке.
• Со мной всё в порядке, не волнуйся.
• Всё в порядке со мной, не волнуйся. — possible, but less neutral

The original version sounds very natural because it starts with the reassurance command:

• Don’t worry

and then explains why:

• I’m fine

Всё is pronounced roughly like fsyo:

• в often sounds like f before voiceless consonants
• ё is pronounced yo

So всё sounds like fsyo.

The letter ё is important because it shows both:

• the sound yo
• the stress

Without it, learners might misread the word. In printed Russian, ё is sometimes written as е, but in learning materials it is very helpful to keep ё visible:

• всё

Yes, depending on tone.

Common alternatives:

• Не беспокойся = Don’t worry / Don’t be concerned
• Не переживай = Don’t worry / Don’t stress
• Успокойся = Calm down (stronger; not always as gentle)

So:

• Не волнуйся, со мной всё в порядке.
• Не переживай, со мной всё в порядке.

Both are natural, but Не волнуйся is a very standard, neutral way to say it.