Genetic testing results

I just got my results from my genetic testing after having a miscarriage at 9 weeks on January 21st. The dr said all tests came back normal and baby was a girl 😢 I am curious if other people have miscarried without chromosonal defects and went on to have healthy pregnancys? If nothing was wrong with her I dont understand why I miscarried. I also just found out I am 4 weeks pregnant right now, 7 weeks after miscarrying, and I have brown blood spotting again so I am now terrified and confused about why this would have happened if tests were normal. My brothers wife gave birth to a baby girl 2 weeks after my loss and my husbands sister is due with a girl in may, it is kind of killing me that I am going to watch my two nieced grow up knowing I should have a daughter of my own the same age as them, I am so afriad these living babies are just going to serve as painful reminders for me and I will never be able to be a proper aunt to them and that if tests were normal than the loss is because of me and my body somehow and that it could be a reoccuring problem, especially with the spotting that has started now. Looking for some info on possible causes if genetic testing comes back normal.