Ttc and feeling low

After trying to conceive for 15 months now I'm getting very discouraged. This month I had what I though were all sorts of symptoms and got my hopes up. Took a test and it was negative shortly after I got my period. Needless to say this month has been the most disappointing month. I was all sorts of excited then found out I'm not pregnant. I'm just at a very low point right now. I don't even want to have sex because I don't want to be as disappointed as I was this month. My fiance keeps saying it will happen just give it time maybe it's not our turn yet.