EX SO is already seeing someone

My so other left me on thanksgiving. I've been handling alright till I saw this photo of him and some random girl in our bedroom. My god it hasn't been long at all. Maybe it's my hormones bc im 26wks pregnant with his kid. But damnit im so angry. I havent even had time to get all my things out of the house or to grieve. Let alone get over us. He says they have only been talking a week but I think it has something to do with why he left me. Im so upset.