Jealous & depressed

A lot has happened in the last few years of my life. I left my verbally abusive ex, found my now fiance who had been the amazing dad my son deserves, and bought a house. My fiance lost his job after a change in management son after buying the house. Thankfully, family helped us through until we got back on our feet. Then COVID happened & I lost my job. Again, we got lucky & I managed to survive off of tax money & the little bit I had saved up. Then a month after finding a new job I got a concussion at work. I ended up having to get a lawyer bc they refused to pay me. Then luckily I got the unemployment I was owed & they son started paying me. I've been having such a hard time dealing with the effects of the concussion. I still get dizzy if I do too much, I get migraines every couple days, my short term memory is awful, & I still can't talk a lot without stuttering, stammering, forgetting words, or even forgetting what I'm even talking about. For 2 years now we've been trying to have a baby. Then in December my brother's wife announced her pregnancy. I was happy since it'll be his first kid, but a bit jealous. Now my fiance's sister is pregnant by accident. It makes it worse that she's constantly said they didn't want another baby because she has thyroid issues & every time she goes off her antidepressants she goes back to alcohol. I'm scared for her because of the thyroid issues. I want to be happy for her, too, (& I am a little) but it's just so hard to be more happy than jealous. I'm already depressed & it's making the jealousy worse. & if his mom asks 1 more time when we'll have a baby I might scream. Thanks if you've read this far. I only have 1 person I can really talk to about all of this right now.