3rd miscarriage in 6 months

Te

I’m at a loss. I’m only 25 years old with no known health problems. I can never seem to make it past the 4th Week. I emailed my doctor and am waiting on a response. For the 1st miscarriage in August I went in and they couldn’t do anything for me except give me an rh shot (I’m O-). The second miscarriage (in oct) I didn’t go to the Dr.

I’m hoping I’m just getting bad luck. If I hadn’t had been taking a bunch of pregnancy tests I Obviously wouldn’t have even known I was pregnant the past 3 times. Does anyone have any advice?