Anxiety with rainbow baby

I got my bfp on Friday and af wasn't due until tom. This is our rainbow baby after 2 losses. I can't see my midwife till Wednesday afternoon to check my blood levels. I'm super nervous because my last baby I lost 2 days after a positive test. My lower back and legs kinda feel like it does when my periods due but I've had 10 positive tests.. Is this normal? Sorry ik I sound pathetic but I'm so awfully scared