All confused

AF came on the 16th 17th and 18th very heavy then she returned on the 26 right on till now but light today this happened 2 months back I'm considered and confused now I don't noe wen my days r to conceive should I go off the first 3 days and start from there or should I go off the second because now I'm going to go I should have my AF on the 10 the fight sometimes I feel like sex is work