please please please help when did I conceive

My last period was on 15th so my dates of ovulation were 29th-3rd. I had a regular partner (let's call him Dave) we slept together on 29th/30th and on the 4th... on the 1st I believe I had drunken sex with somebody else (we'll call him Michael) but I'm not sure as I can't remember exactly. I told them both I was pregnant and there is doubts over who is the father. Michael says he used a condom and I believed him then he changed his story and said nothing happened at all so I can't trust what he's saying. Michael then changed his story again and said there was a different guy called Josh that I had sex with - this i don't remember at all. I was so drunk and I am so upset that I cannot remember the details. My most likely date of  conception is probably the 1st as it's right in the middle but I just don't know. I think there is more chance of Dave being the father but the dates don't quite add up. My cycle is 30 days but I realised glow had been tracking my period as if it were a 28 day cycle so my most fertile day probably wasn't the 1st. And if it's not Daves and it's not michaels then it must be Josh's, but I haven't even spoken to him at all because I'm highly doubting whether that ever happened? I don't remember a thing I'm so ashamed. Who do you think is most likely to be the father, or when do you think I conceived?