Cycle day 35 no af, extremely tender breasts, some pain on right lower abdomen, extremely tired, negative hpt? Please help!

Maybe a cyst? Irregular cycle, pain, and hormonal symptoms can all be related to an ovarian cyst. Cysts are common, and they usually resolve on their own. If your period doesn't come soon, or the pain is significant, then make an appointment with your gyn to get an ultrasound.