Confused

Nerrisa
My partner is 36 & Im 37 both have 2 kids to previous marriage & would love to be able to blend our families together by having a child together, we have been TTC now for nearly 7mths & have had no luck, I started out with using just a <a href="https://play.google.com/store/apps/details?id=com.glow.android">ovulation app</a> to find roughly when I would ovulate then last month I thought I would try a OPK as soon as I got a positive it matched the 4th day of my fertile window & well we all know what happens but still AF decided to visit so this month I went by the predicted fertile window & still a BFN it's starting to get me down in the dumps & thinking it will never happen.... Should I go see my GP? Am I too old ? Is our dream of becoming parents again over ? Or am I just overthinking this ?