Pregnancy after abortion

I had a medical abortion the end of February for medical reasons towards my health. The baby would not have survived full term. I was only 5 weeks along when I had to take the pills. I got on birth control right away so I wouldn't have to go through this again because I will never be able to carry a pregnancy to full term. I've only had sex 4 times since the procedure. 3 times the third week and once this week. The only thing protecting me was the pill. My bf and I were very careful those 4 times and he pulled out before ejaculating (I know this method doesn't always work but remember I'm on the pill) I got my first period last week but it only lasted for 3 days. Ive been having some lower back cramping and I have to go to the bathroom more frequently and I'm really nervous I could have gotten pregnant again because I know it's possible to right after having an abortion. Im not sure if it's just my nerves or my intuition. I want a family but like I said I can never carry a child to full term through a pregnancy and I don't want to have to go through this again. It was very emotional for my bf and I. Please keep your negative comments and thoughts to yourself. I just need some advice as to if I could possibly be pregnant again. I'm also iffy on taking a home pregnancy test because I know the hormones can stay in your body for 4-6 weeks and it's only been 5 since my procedure. Thank you.