Concerned

I don't know if it's dumb to ask this, but are blood clots during periods normal? I'm on my period, but I feel like this one is different. I've been having clots the whole week. It's Friday and my period end on Saturday, so my flow has been decreasing but I just had a clot that was kind of big. I'm on birth control, so my past periods have been steady and just fluids. I've never had this happen before and I think I should ask a doctor. I just wanted to know if this happened to anyone else too.