It's nothing you're doing wrong, sounds like pre-eclampsia, if you have it, you'll probably have regular check ups (more than normal) to keep an eye on baby, depending on how bad it is you may have to be admitted to hospital.good luck momma :) try not to worry :)
Happened to me im 38w+2d and they said my blood pressure was high sent me to the hospital and it was normal. They also said I had protein in my urine made me pee in a cup for 24 hours . Everything fine with me now
I'm 33 weeks with my first pregnancy and now I'm scared I'm doing something wrong! !