Difficulty conceiving baby #2

Think today I just need a bit of encouragement from other women who are in the same boat as me. I turn 34 this weekend & DH is 39. We have a 7 yr old LO & have been actively TTC our second child for a year now with no success. 
When I started this journey last year I never thought for one minute that it would take this long. We conceived our first child on our first real try & I don't think I ever truly appreciated how lucky we were until now. 
This month i really began to suspect I might be pregnant. It was an unusual cycle, i ovulated earlier than usual & my bbt was showing a promising triphasic shift. My temps usually drop day before AF is due, but this month it kept creeping up, also AF always arrives 14 dpo,  but this month she was a no show. I bought a test & as I drove home I allowed myself to think about getting that long awaited bfp & how & when we would announce to family & friends that our little bundle of joy was on the way. 
My hands were shaking as I took the test, but as I waited the line never came. The test, like so many before, was negative.
I know I'm lucky to have already been blessed with a child & I never forget that. However, the disappointment of each bfn keeps getting harder to bare.
 We've begun tests to find out what could be causing the problem with conceiving but we already know that we won't be eligible for <a href="https://glowing.com/glow-fertility-program">fertility treatment</a> on the NHS because we already have a child.
So far I've taken this journey one step at a time & remained positive & optimistic at each turn, but today I feel sad, I feel negative, I feel disappointed, I feel hopeless, I feel helpless, I feel frustrated. I also feel a little bit like I'm not allowed to feel this way because I already have one, like people don't expect it to hurt as much  because I'm already a Mum. The thing is emotions don't work that way, beginning to suspect that I may not be able to have another child is nothing short of heartbreaking.
Not sure if any of you are going through the same thing or have gone through it before but it would be really good to know I'm not alone with this. 
xxx