Help please

So my story is kind of long, in april i had sex with my boyfriend i had gotten my period on the 3 and about the 16 was the day i had sex so by my birthday the 19 i felt super tired all day i had no desire of going out i just wanted to be in bed my eyes would literally close by themselves. So i ended up going. A couple of weeks before may like a week before instarted having cramps and belly pains and i though oh hey my period is coming and it didnt come on the 3 of may i went out and had sex with another guy my friend and they days passed and i still didnt have my period by may 10 i was scared because im regular so i tested myself and came back positive. It made me scared because know im confused whos baby is it really the first guy or the second? My due date is supposibly january 9