I always wondered how I would feel if this happened


So my boyfriend and I have been trying to convince for 4 months now going on the 5 month, and I always would come in this community and look at all the people that got pregnant and I would feel so happy for them but I always wondered how I would feel if it was someone I knew. Now I do understand that there are people dealing with infertility for years and years and that I'm only in my 4 month. But every month becomes a little bit harder and a little bit scarier. Yesterday my brother in law texted my boyfriend telling him that he and his girlfriend were expecting and I was filled with rage that I didn't know was possible. Now some backstory, he has only been with his girlfriend for about 2 months, his girlfriend has 3 year old twins and my brother in law has always had this competition thing with my boyfriend for some reason, kinda like copying, when we decided to move out of his mom house, his brother suddenly wanted to move out too, when my boyfriend bought a new car he bought a new car and the same exact car, when my boyfriend told him that we were trying to convince he tried to convince my boyfriend to not. And I don't know how to deal with it because I know for a fact they were trying to convince it wasn't an accident, and I know that they can't afford it because they both live with their parents at the moment. Me and my boyfriend are ready for a baby and are in a good position to have a baby economically. I feel guilty because some thoughts came to my mind for a second that I'm not proud of, I feel sad because it's not fair and I feel rage because if the reason he's having a baby is the one I think it is, its stupid and it should not be a reason to have a baby. I know I ranted for a little bit I just need some help on how to deal with it and how to keep my cool and focus on my future baby. Thank you!