Can birth control affect my period??

I was on birth control for a month then ended up being off of it for two weeks (bc it didn’t get shipped in time and I was gone on vacation) and now I have been back on it the last 3 weeks.

I was supposed to get my period but it hasn’t come yet. Could I be missing/late on my period bc I have been starting/stopping/restarting my medication?

Also, I took a pregnancy test this morning and it said I wasn’t pregnant but yesterday I started getting slight pain/discomfort in my right lower abdomen.

I’m nervous and I don’t really know what I need to be nervous about lol

Update: this is also a really stressful time right now bc my boyfriend just left for college so I’m all over the emotional map😅