I had an abortion a week ago, I was feeling nausea a bit but now for last three days my lower abdomen really hurts, sharp pain. Is that normal?

Need evaluation. You need to present to the ER for evaluation by OB/GYN. Pain can develop postabortion from postabortion syndrome / hematometra which includes severe abdominal pain from retained products of conception that the uterus cannot expel,bleeding,uterine atony. Perforation of the uterus or bowel can occur, and ectopic pregnancy may have occurred. ER visit ASAP.