EMERGENCY!!! NEED ANSWERS ??

Nanganak ako last nov 1,2019 then after two months i got my injection last January 6, 2020 (yung injection para hindi mabuntis) then after i got my injection, merong rule na for the first seven days wala mun dapat sex contact para maabsorb ng katawan ko yung gamot. Pero di ko yun nagawa, halos araw araw ako may contact kasi mapilit asawa ko. and now, after one month i got my injection, February nilabasan ako ng maraming dugo na may bilog na malaki. Ang sabi naman nila kung duduguin man ako dapat spotting lang. Pero bakit kaya ganito? Ano kaya ibig sabihin nito? Need help mommies!!! ????