could I be pregnant?

Maggie
I have always had a very heavy menstrual cycle that has always consisted of a perfect 7 days. For my last 3 or 4 periods, they have consisted of bright red, sometimes heavy at first, to then super light and sometimes it's just spotting all together then nothing. And then sometimes a random glob of brown will come out. I have had unprotected sex almost every time with my boyfriend. I have two kiddos and with both pregnancies I missed my periods. Just wondering if this could be a sign I'm pregnant? But also feel crazy for thinking this because you shouldn't bleed every month if you're preggo. Any input is very helpful! Thank you!!!!:)