BFN - need hope :(

La
So once again I'm out, been ttc for 15/16months now and had 3 months Clomid.... I'm just at a point where I think we are going to have to give up! I don't know what I'm doing wrong anymore? We have had a stressful time and the hospital said they don't think that's helped but unfortunately sometimes we don't chose these situations and we all go through them,  Iv gained 6lbs like they said and sex every two days?
I'm unsure where I ovulate as I vary some months between 28-33 but I am so worried that there's something else wrong with me! 
I'm at a point now where I think do I go crazy and don't drink coffee ( have 2 max a day ) completely stop drinking alcahol? I don't go out much but have the odd glass of wine across a week? Don't eat a lot of red meat mainly carbs and chicken? Do I need to exercise more? Sex every two days this time as well and still not worked!
 :( 
I just don't know what to do anymore really need some positivity and hope! 
My partners very supportive but I know it's hard for him as well but I seem to spend the "two week wait" excited at first and hopeful then very anxious and scared that we've missed it again then feel like I disappoint him when I continuously say it's another negative. 
Think it's a weepy day for me never thought I'd cry so much just ttc. Sorry for whinge was really hoping this was our month. Any advice would be greatly appreciated.
Still sending lots of positive baby vibes your way for those of you ttc and for those who have already received the BFP. :)