Pregnant after 4 miscarriages

Hey after 2 years I got pregnant I had 4 miscarriages and I’m stressed out about this pregnancy I really want it to go well I tested positive I’m currently 4weeks pregnant having my ultrasound in two weeks but I got one negative test which bothers the rest are all positive I mean I don’t what to expect as I had few miscarriages and don’t want it to happen again any useful advice as how to prevent that happening here are my positive test and the negative one