My breasts are tender at headance, I'm feeling off and have mood swing…

My breasts are tender at headance, I'm feeling off and have mood swings. My weight has increased, my mister says it's because I've gained weight. He said I should eat more often as I am always hungry and I feel nauseous. My sex life is active but now it's irregular. I know I've been on my period for two months, last period was September 29th, I should have had it by November 29th, but I had it last week of December. But for me, I'm positive that I might be pregnant. What could this be? Please help.