Who can the Father be

Hi you guys. I cant help but stress because i do not know who the father of my unborn child will be. Today i am 25 weeks and 4 days and i believe the start of my LMP was February 3, 2016. I was with Father A from February 13-21 we had unprotected sex and he came all in me. I left him to go to my ex Father B and was with him from Feb 22- March 14. Me and Father A have been trying to have a child for. 6 months and my period would always come so i thought i was infertile. Then i found out i was pregnant March 14.Please help with your opinion thank you