anyone going through this too?

hey ladies my husband and I have a 18 month little girl we been TTC since June. no luck.i am 22. I had what I thought was a very faint positive 2 months ago but was severely hurt when AF showed. nothing seems to be working to get pregnant. it took us 4 years to conceive my daughter. as the months slowly disappear I find myself getting so sad. I was doing ok then 3 of my friends not trying to conceive just announced they r pregnant. I didn't know getting pregnant could be this hard. :( any ladies going through something similar?