Suggestions please

Sooo... I am currently pregnant 23 weeks 5 days recently I just found out my fiancé mother called my doctors office without my knowledge too see if she could schedule a procedure for a DNA test! So of course I’ve been heart broken! So here is my issue, since then my mind has just been all over the place... I had a boyfriend at the time before I got with my fiancé now. Me and my boyfriend broke up on September 10th, I had a period at the end of August beginning of September and then another period at the end of September for 5days! On October 16th I tested and it was a faint positive. And me and my fiancé had got together after me and my boyfriend broke up! I went to the doctor November 21st and had an ultrasound and I was 8 weeks 3 days... is there anyway possible it could be my ex baby? My fiancé mom seems too think I was pregnant with this other dudes baby... I need some help