Instinct?

Hey girls,

I had something weird happen this month. I got my period normally. I felt my ovulation. I had sex after that and thought I had implantation after 4 days. I only had a little bit of brown discharge and a panty liner was enough. The next day I had very severe pain and lost a lot of blood in 2 hours, but after that I lost almost no more blood. This was one full pad (sorry for the details but maybe useful to know). The next day I didn't bleed anymore, only brown discharge when wiping. I still have a lot of pregnancy symptoms. Nausea, frequent urination, headaches, etc. I don't know if this can happen so early, but I also saw blue veins on my breasts that weren't there before, or I never really paid attention to them. But as far as I remember, they weren't there before. I'm going to take a test on Wednesday.

But has anyone experienced this and was still pregnant? Was this a miscarriage or just a heavy implantation since there was a lot of blood once and I didn't bleed anymore after that?