grrr af delayed then came today :(

Amanda
This is my 4th cycle trying, I'm 36 & no luck so far. My periods have always been 25 days on the dot but the last 2 months have been 28/29 days in length. I'm not taking anything hormonal to cause this nor was I on the pill prior to ttc.
 I'm really bummed out today as I was so hopeful i had a brown spot several days ago & then today woke up crampy & af showed before midday. I'm So frustrated & don't understand my body right now...I'm worried I am getting close with af being delayed but worried maybe I'm being delayed as I just can't get pregnant...,I've had all my pre conception tests done & my bloods appear ok.
 I know it's early days but I still can't help get frustrated especially when I'm just getting older :/ has anyone been in this boat & eventually succeeded around my age?