I had sex with someone on may 18 , the someone new June 25 and had a short period in the beginning of June is there a possible chance that may guy is the dad

You'll have to wait for the birth and get a DNA test done to resolve the paternity.

As Curlyben said, DNA testing will let you know for certain who the father is.

When is your due date? How far along are you thought to be? Have you had an ultrasound and, if so, when?

How far along are you? Its going to be hard to know since it was oonl not even a month apart. But you should find out how far along you are. But like they said your most likely goiing to need a dna test hun