Does this mean I'm infertile?

I don't think you are infertile. I have been TTC for 11 months know and have a 6yo. I have been working with my Gynecologist to see if there is a reason as to why I can't get pregnant again. The fact that you are getting, and then unfortunately miscarrying, means that you are not infertile. You need to find out why the pregnancies aren't holding. I suggest talking to your Doctor, good luck.