Not pregnant but need help!

So first off- me & my boyfriend always have protected sex ! We have never 1 time went without a condom nor have they broke . Weve been having sex a lot lately & my periods have been irregular these past few months. I didn't have my period the whole month of January & now March. I got it in February & December tho . These past 2 days I've been sick with what seems to be sinuses & allergies because of the weather changing so much . But late last night I was having really bad vaginal pain & abdominal cramps & I've been having a lot of CM which is watery & clear. There's no way I could be pregnant but idk what this could be .