I have unregular periods

Okay. First let me explain my cycle. I have un-regular periods. Usually 30-31 days long. Which means i should ovolate 14-16 days after my period starts. Well.... 10 days after my period started I was at my boyfriends house and we had sex (protected with a condom with spermicidal lube) now the sex went great with no probs and the condom didnt break. After the sex we went and i peed and he washed his hands and then i washed mine. But he wanted to finger me again. So anyways i go to sit down on the bed and hes all like "hey dont sit in that" and i look over about 6 inches and there is a (im not too sure about this part) but it eather went down one of two ways: 1. There was the condom laying there on the bed and i spilled it getting on the bed. 2. There was sperm on the bed when my boyfriend spilled it taking off the condom. (I remeber that it didnt break inside me because i looked at it when he pulled out and the sperm was clearly inside the condom)... Anyways back to the story. I didnt sit in it or touch it, but if #1 situation occured my boyfriend picked up the condom (may or may not have got sperm on his hands) then took the covers off his bed) but if #2 happened then he just took his covers off his bes and everything is good but the sad part is I DONT REMEBER. So still assuming it was #1 instead of #2 then my boyfriend put his fingers in his mouth for lube and fingered me. Now its one days until my period and im worried. I dont have any pregnacy symthoms but sore boobs and i sometimes get those before i start. But they stared hurting around sunday. Sooo anyways... Today is thursday and its 14dpo and 18 past the day i could have got pregnant. I took a dollar store pregnancy test and it said negitive. I have another one and im gonna take it tomorrow morning. But Do you guys think im pregnant? Can i trust the test?