Why is there painful lump on my lower abdomen? 😞

Hi, yesterday I pressed my lower abdomen (between belly button & pelvic bone) & I feel a little lump in the middle or a just little bit to the left I would say. I freaked out at first because I never felt that before & I rarely press there too. Today I pressed it again and it feels a little painful. I don't think that I'm pregnant coz I practically a virgin & never have sex/intercourse involving penetration, but I did have oral sex last month (can precum in my mouth transfers from my guy's mouth & to my vagina causes pregnancy? I know this sounds silly but I'm quite scared too ). Btw, I did take home pregnancy tests this week & last two weeks (total 3 tests) and they all came out negative. My next period is expected for another 1-2 days. Could that lump possibly be there because of my oncoming period?