Little bit of a rant..... Really long.

Ok so I'm not looking for sympathy here just needing to vent a little bit and you may even think I'm kind of a b**ch after reading this but that's ok..... My best friend/SIL has a two year old little boy with a seizure disorder and is trying to convince but her husband doesn't want anymore kids..... Anyways I'm 29 weeks pregnant with my first and am super excited and everything is going well so far! 
Background info--My hubby and I have our own place, just got married and both have decent jobs. When she got prego with her son, her and her now hubby had just broken up and had gotten together one night for sex, she still lived at home and she was pretty young. She had a horrible pregnancy.... Morning sickness the whole time, many different colds, gained lots of weight and many more things. They ended up moving in with her mom and having the baby and eventually moved into there own place. And they had been engaged for three years then when my hubby and I got engaged and announced our wedding date she decided that they needed to get married before we did so she picked a date that was 3 months away so everyone was running around trying to help her throw her wedding together and kinda forgot about my hubby and I... Which made me mad to be honest but I got over it. I think they ended up staying together because of the baby so now her and her hubby fight all the time and she's not really happy.
When we hang out all she can talk about is her son being sick or wanting another baby and being able to do it right this time, and I feel like it might not have been perfect but they made it and she doesn't see it that way and just complains about it all the time and makes me feel guilty for everything going smoothly with my pregnancy/marriage and I don't no what to do anymore.... It's getting to the point where I don't want to hang out with her much anymore because she just puts me in a bad mood. Do you guys think it will pass once my son is born? Any suggestions?