Am I pregnant

I had sex and a day after I started bleeding and now Iv been bleeding for 3 days. It’s a light bleeding, enough to ruin my panties if I don’t have a panty liner on them, My nose has been stuffy and stopped up since then (it’s like my allergies are kicking my adss rn) and Iv been sneezing a lot. This morning blowing my nose I had a nose bleed (not the same nostril that Iv been having nose bleeding in every now and then in the past couple months. I went to my doctor a while back and he said if it’s the same nostril every time it’s normal but it’s not the same one this time) sometimes when I get up I feels light headed. I realized Wednesday that I was a day behind on my birth control so I took 2 pills Wednesday and I started bleeding Tuesday I’m supposed to start my period next Wednesday and I always start on the same pill of every pack. Iv been on birth control for 4 years. Can someone tell me what’s going on?