implantation bleeding?

My period is not normal . I got my period feb 23- 26th then I had sex the 4th of March with guy 1 (Being kind of forced too) we used a condom but the first two time he put it in he did not have a condom. It did take him forever to finish when we put condom on it was just not enjoyable at all but then on March 11th I had what I think was my period. I don't think its implantation bleeding Bc my period was from March 11th - March 15th on March 14th I had sex with guy 2 (my ex & yes on what I think Is my period) we didn't use protection at all and we continued to have sex with no condom . April 3rd I took a pregnancy test & came back positive. Whose baby could it be? I want to say my ex since the blood from our first sex was a lot not a little like implantation. I remember during the sex I had to grab a towel Bc I just had too much blood. That's why I think it's not implantation. So who could be the dad ?