I just need to vent

I'm 21 years old and I've experienced 5 miscarriages and my 6th on today. I'm just frustrated with life, I see women having baby's all the time and I don't understand. they have no worries in the world, and I can't help but be terrified everytime I find out I'm pregnant because because the world has robbed me of that. They have no answers as to why my first four happened, my fifth was a partial-molar, and my sixth is just an "early miscarriage". I've had tons of testing and they even tested my chromosomes and can't find a reason, they keep saying "you're perfectly healthy" but the shock on doctors faces when I tell them my age and how many miscarriages I've had tells me something isn't right. I just want a light at the end of the tunnel.