Hi kassi90
That's a pretty crazy dream. A lot of the content ,may mean nothing. As many dreams are odd.
I do not know your life's situation. But when you see yourself having sex with yourself (it would be easier this way) I think to myself...Fear of a relationship? Fear of having sex for the first time? Fear in context to some sexually oriented experience.
When you see it is your friend. IS this friend the same sex or someone you admire? Are you competing for some one's relationship --hence the race..maybe!?

I have to give some off that other dream content some more thought.

What are your gut feelings?