I’m so sorry you have to go through all that! I don’t know why hard things happen, but I think some reasons might be that we all have agency and that we need to learn. Since God has given us our agency, some people are inevitably going to use it in less-than-optimal ways. When you give billions of people free will some are bound to use it to hurt others. I think sometimes hard things can also teach us things, or put us into positions to receive blessings that we wouldn’t get otherwise.
I’m not saying that these are why all hard things happen, but it might explain some of them. I, evidently, often don’t know why God does what He does. What I do know, though, is that He won’t leave you to face it on your own. “I will not leave you comfortless: I will come to you” (John 14:18). Even if He doesn’t help you in the way you’d expect, even if you might not even see it, He’ll still be there for you through it all.