Correct usage of "of course you (do/are)"

Compare

Of course you do having trouble finding your car.

with

Of course you are having trouble finding your car.

If A uses “having” (present continuous?), then B's answer should be in the same tense.

The other form would be:

A: I have trouble finding my car.

B: Of course you do.

Rule One: If the verb is modal*, then match the verb:

The verb used is to be (I am/I'm, You are/You're/, He is, etc.) because the verb in the first sentence is am though contracted to I'm.

The response therefore would use that verb too, but in the second person; you are or you're.

We tend not to end on contractions, so "Of course you're" would be strange, and so it's "Of course you are".

Rule Two: If the verb is not an modal, then you use do.

I found my car.

*Of course you found. [Incorrect]

Of course you did.

Rule Three: If the verb is not followed by an object or preposition, and ends the sentence, then you can choose between the two:

I don't dance.

Of course you dance.

Of course you don't.

*The modal verbs are be, can, could, dare, do, may, might, must, need, ought, shall, should, will and would.