Breakthrough bleeding?

Elizabeth • PCOS, Twin boys- clomid / baby boy #3 naturally

Ok so my husband and I have been TTC for 3 months. I had been nauseous, My period was about a week late but all tests showed negative. Then today I got my period but I’ve ALWAYS had extreme pain due to endometriosis and a heavy flow . Today when it started I has zero cramps which immediately was off for me. A few hours later the cramps hit but not as severe as usual and only for about an hour. Usually my cramps last the first three days of my period. Also a medium to light flow when I’m use to heavy- extremely heavy. Could this be breakthrough bleeding? Would love to hear your opinions and personal experience!