Ttc for 6 months

Audra
This is my 1st time posting
I have 3 kids already. 16,14,9 yrs old. 
My boyfriend currently wants a child and am willing to give him that joy. We have consistatly been trying to get pregnant for 6 months and haven't been on bc ever. We have been together for 2+ yrs. 
is there something wrong? I always get a heavy long period monthly too
Any suggestions?