I'm 26, upset stomach, can't eat, abdominal swelling, bloating, always feel full, irregular cycle, can this be ovarian cancer, not on bcp, never had sex?

Cancer unlikely. Typically ovarian cancer has no symptoms until they are very advanced. Your symptoms are nonspecific, an don't point towards a single diagnosis. Ask your doctor if you could have irritable bowel syndrome, or if a referral to a gastroenterologist is appropriate. They can also do a proper evaluation. Hope this helps!