3 early miscarriages in a row around 5weeks - HELP

Hi everyone.

I’ve got a 2 year old so I know that I can have a healthy pregnancy. Since then I’ve lost nearly 8 stone, you would think this would help pregnancy. I’ve since had a miscarriage in August, October and now going through my 3rd. I can’t seem to get past the 5 week mark despite falling pregnant quickly after each time. Anyone experienced anything similar? I’m just worried now there’s something wrong with me. I tried taking baby aspirin this time which didn’t make any difference. X