Please help me getting discouraged

Hello beautiful ladies so this my 5th month ttc and my cycle length is 35 days and period lasts 7 days after my period on dec 17 I was testing with opks till I ovulated on jan 16 (cycle day 31) but I was confused because I was suppose to get my period on jan 20 and now it's been two days and af has not shown up I'm on cycle day 37 today I've been having stomach pains and I think cramps not sure I get really bad sharp pains in the middle which hurt really bad please help me I'm really confused I want to be pregnant and I'm hoping has anyone's gone through this and what can this be