Getting frustrated..TTC!

Is going by the calendar on here working for any of you.? I’ve been ttc for about 3 months now and nothing has happened. I’m having trouble understanding about the cm and things like that..I have sex every other day especially around ovulation time but I’m thinking the calendar may be wrong or something. I’ve also been having two periods a month since last month and not sure why. Can someone fill me in and give me tips to help me out..thanks in advance!