Bloating and weight gain at 6 weeks

I can’t believe I’ve already gained like 4lbs and I’m only 6 weeks. All my clothes are tight and even my maternity bras don’t fit ... I suppose maybe it’s a good sign Bc my last two pregnancies which ended in miscarriage I didn’t feel like this. Does anyone know How much weight you are supposed to gain in first trimester?? I heard 25 overall and 4 seems like a lot to me already. I don’t put on weight easily and am average (not fat) so it’s surprising. The problem is I always fe hungry! Lol