I had intercourse on the May 6th with someone i was seeing, i then got my period May 8th. On may 15th I had intercourse with my ex (now boyfriend again), I am now pregnant, who is the dad?

Another young person who failed to keep her legs closed during all of this drama.

Flip a coin.

Not me

Please name your babygirl JaNickka.

Your babyboy  Jaysen Andrew.

Given the sexual activity from May 6 to May 15, I wondering if those two are the only candidates.

And is this just a curiosity question or does it matter who actually is?

Colonel Mustard?

Nobody, yet.
A "dad" is the guy who takes responsibility for helping to raise a child.

Considering that was 5 months ago .. It is now October .. And you are now just pregnant .. Figure it out yourself. It's too obvious to even bother to answer.

If however you conceived in May (by chance) and only now (5 months later trying to figure it out) .. the only way to figure it out is to figure out when you ovulated .. you have a very small window of opportunity to actually conceive during your cycle. 

You're gonna have to get a paternity test.