20.. confused! Is this breakthrough? Should I be worried?

I’ve been off my period for two weeks and have been spotting light brown for a about a week. The first day I started spotting I was having small cramps but that went away after the first day. Now I’m just spotting when I wipe. Is this normal? I’m kind of scared because I just started being sexually active again. Also I’m on Nora be and have been for about a year. I always take my birth control at the same time. Is this breakthrough? Should I test to be safe? Or am I just being paranoid! My sister had two kids while on birth control... I’m trying to avoid that!! Any info will be appreciated. Im going to insert a picture of the blood. Oh yeah, and I’ve had some stringy discharge if that is even relevant!

I’m sorry if this is a dumb question I am just nervous!! Thanks!