Blood 2 dpo

After dinner I had cramps, and I was feeling nauseous. My back hurts. I went to the toilet cause the cramps didn't stop. And I had blood on the toilet paper. I first thought it's not from my vagina. So I wiped again, but now I have more blood also when I'm walking and sit on the couch. Anyone who knows what this could be? I'm 2 dpo.