Starting to get a little depressed

I have a daughter but my bf has no kids of his own.. we've been trying for almost a yr..I also had P.I.D 2 yrs ago... my cycle isn't very regular so when I'm a week, a week and a half late I get so hopeful I go through the motions.. sore boobs, nausea, mood swings... then my cyle starts and I get sad... I also feel it's not fair ppl I know are like oops I'm pregnant, oops... oops and I'm here actually trying like what the heck? Everyone keeps telling me to "stop trying so hard", "it's because you want one so bad".... it's to the point I think I'm making my SO feel bad!