Don't know how to feel

Jordan • Eliana Rose ♡ 03/24
I'll try to keep this short!! This is just to get all my anger out and hear what anyone else has to say... 
Been with my boyfriend for almost 4 years, his sister and I both have cysts. (I have pcos and she has huge cysts that rupture, not sure specifics) but these cysts stop us both from conceiving. As far as I knew, she was not ttc. She has been with her boyfriend who is 5 or 6 years older than her for about a year.. He has two other daughters with two other women!!!! Okay, so my boyfriend and I have been ttc for almost 2 years, gone through a miscarriage before. Our families are not aware. So a few months back, after not ttc AT ALL and being on the depo shot(I think she came off when conceived though) she somehow managed to get pregnant... And I'm so tired of hearing about her son and her pregnancy and all her disadvantages of being pregnant when that's the only f-ing thing I want!!!! Full blown morning sickness, pregnancy brain to the max, and body aches like no other.... I'll take whatever. But then there's her who constantly complains!!!!! OH and on top of this, right after they found out the sex, they got engaged..... They all still live at my boyfriends parents house. Now it's easier to save money, we're doing the same thing( I don't live with his parents, but you know what I mean).. But his two kids stay there every other weekend!!!! And it's an apartment, they don't need much room in the first place. But now she'll have to find somewhere to put a baby, and I'm just so frustrated and don't know what to do.... I'm possibly pregnant right now but consistently get negative tests, just a feeling though(and 20 day late period) but why her and not me??? I don't get it 😡😡😡
My apologies for the long post, I hope someone can give me some advice and kind words to make me feel better