My period is irregular, I had intercourse with my boyfriend and I am paranoid, the test is negative

So my period is irregular at times. During spring i used to get it near the 25th and then during the summer i switched to getting it near the 20th and out of no where in november i got it on the 12th. And in November my boyfriend came over on thanksgiving so the 27th of November, and we didnt necessarily have sex. I mean his penis did go inside of me but i made sure that he wasnt leaking or anything. I basically cleaned his penis before he ever went inside of me. And it wasn't like full on sex either bc he just went i side of me and came right back out. We had never done this before bc im so paranoid about sex and i always make sure that the condoms don't break and everything but this time idk why i gave in. Anyways, i was expecting my period on the 12th; it didn't come. So my friend bought me pregancy tests and i took one 15th at night and it said negative (btw i used first response). And i thought well maybe all these symptoms are just a coincidence. Bc days earlier i had been feeling a bit nauseous but i was also just sick; i had a stomach bug. And i had a lower back ache for about a day or 2 and i had discharge everyday and also i had been have veey short stomach pains. So i waited about 3 or 4 days later and took another test. I guess i didn't do it right this time bc it never showed a result until after 3 hours, so that one was unreliable. It is now the 21st of December and still no period. Im really getting worried now. My breasts have been sore too but idk if they're actually sore or if they're sore from me squeezing my breasts every now and then to check if they're sore. Any feed back could really help! Thank you!