Really down please help

Been TTC our first with my hubby for five months now. He is 41 and I am 38.

We are doing everything, BD every night over fertile week, using OPK, vitamins, Preseed. Tried every position.

I know that people say it’s takes a while but it’s getting me down.

My sister had her third last week and they weren’t even trying, it was an accident!

Everyone is gushing over her and I just feel so inferior to her and it’s getting to the point where I get so down every time we have a family gathering.