I'm sad

So I'm not sure if I'm the only one who does this. Every time AF starts I have this positive feeling that this cycle I'll be able to conceive a baby. But after BD during my fertile week I get negative thinking " why is this month different then last month, I'm probably not going to get pregnant this month" and get all depressed and cry for a whole week. I'm on my tww right now and I've been crying because I'm being negative. Just wanted to share because my SO doesn't get why I'm crying over this.