My stomach get swell and bloated. Woman?

I m 22 years old. In October 2016 i was 1 month pregnant and i had done medical abortion. After that my urine test was negative and also ultrasound report says negative pregnancy. After that i had menstruation cycle every month sometimes with a difference of 5-7 days. 2 months agomy stomach gets swell when i chck up two stones were found in my kidney whoch are removed but now my stomach is swell and bloated likea pregnant woman. Ultrasound says everything is normal and also i had my periods are normally done this month. Also pain in lower back. Alsofew days ago a small piece with blood is came out when i was pissing.why i still gets bloated stomach like a pregnant woman? Is it a vaginal infection Is i m still pregnant Is it is cryptic pregnancy