I know this seems slutty, but I have been with the same guy on and off for 5 years.. we used to sleep together all the time and he would pull out and I have never gotten pregnant.. We slept together 10/30 and then we got into a huge fight and eh said eh was done with me and I went out drinking and ended up sleeeping with someone else, this was 11/6... The boy I have been on and off with called me and apologized and we ended up sleeping together 11/09 and then went back with the other guy and slept with him 11/12... I know this was wrong and I feel disgusting for this but I guess I was trying to get over my ex by being with someone else, but in reality still wanting my ex whenever he would have me....I have taken home prego tests bc my boobs have been sore and I was supposed to start my period 11/6 and haven't .. the home prego tests came up with dark horizontal lines and very very light vertical lines.. and i went ot the docters and it came up negative but the nurse told me that if I didnt start my period in a week to come back and retest.... Is there any way to try and determine which guy could be the dad IF I am pregnant? If I happen to be pregnant would an ultra sound narrow it down?