Itching

I’ve had severe itching. Started with my feet and hands and now it’s all over. I told my ob and he told me to put calamine lotion on. I’ve tried it for a week but it’s not working. My sister told me to ask them to do blood work because it can be cholestasis. I’ve asked twice in the past 2 weeks and now he’s recommending Benadryl. I’m currently 29 weeks I’ve thought about changing Obgyn’s but I think i might be too far along. I don’t what to do at this point.