why does this happen?

Sorry for the long post and just rambling on. I just had to get write it down, sometimes it helps. I know it may be alot of run on sentences and there may messed grammer. Sorry in advance. And if you read it all, props to you. lolSo here I am thinking I'm never going to be a mom! I just don't understand it. I blame myself multiple times because growing up I always wanted kids, then in my 20`s I decided no I didn't, or atleast right then and there. Her I am about to be 31 going what the hell, why didn't we try sooner and be more proactive about trying. Even at that were not very proactive now, sure we have sex but not a whole heck of a lot, we don't use protection( heck we didn't use protection for 7 years). My doctor says he wants to run some testing on us but of course our health insurance doesn't cover anything with fertility, and right now were trying to save money to be able to buy our own house. Sorry I know I'm rambling but here's the thing in October of 2017 I got pregnant but I didn't get to excited because I had only very light positives and was like they got to be darker then that. I kept taking tests they would get a lol darker but not the strong positives you always see. I called my ob and they told me as long as there is a second line it's positive. So I started to get excited, my husband was saving baby outfits he liked, we were picking out names, talking about the future, I know a little early for all that but we did. Thanksgiving rolls around and my husband and I was cooking for the family, I was on my feet all day. That evening we decided we wanted to check out the sales going on so we went to the mall, I kept having these bad pains in my groin and I didn't think much of it for a little while because I had been having groin pains all along. But these were horrible, we go home and I try to get comfortable but can't, I take shower because now my back is killing me, and I feel something and of course it blood. I had a miscarriage. It sucks it broke my heart. i cried for awhile, I really wanted this child. Fast forward to now, I had been feeling off, nausea, very exhausted(like I could sleep for days), boobs are sore, food aversion, boobs are bigger, just feel pregnant. I had spotted a little at the end of February but not enough to consider it a period. So I thought maybe I am pregnant, I give it some time, my next full blown period was suppose to start yesterday and nothing. So I go and test, and there's a very faint line( I thought the faint line was maybe because I had been peeing nonstop all day), my cousin even sees the line. So I'm pretty excited, I woke up this morning and took a test and nothing it's negative not even a faint line. So I go back to sleep and wake up again a couple hours and wipe and I'm spotting very very lightly and light pink. Here comes aunt flow, I feel cramps in my hips and everything. So I'm let down and now all I can think is I'm never going to be a mom, Never! Ughhhh