Extreme itching!!

I am 21 weeks and a very high risk pregnancy, have had multiple losses and complications before. I was on progesterone injections until about 2 weeks ago and I am still currently on blood thinner injections.(long story) Around 2 and half weeks ago I developed this itch, I played it off first thinking dry skin or my skin was stretching from the pregnancy. Since then I have used multiple lotions and oils, even benadryl nothing helps at all. It has increases especially at night, to the point I've made myself bleed a couple times. I told my doctor about it in my last visit, they checked my liver through blood work and said it came back fine. The itch is still so awful I cant even sleep at night anymore. Anyone have any idea what this could be??