Weight gain 8 weeks

LL

I am only 8 weeks along, and I’ve gained about 6 pounds (3kgs) and gone up a bra size already. I’m eating very healthily, though not exercising (I’m exhaaaaaausted!!!). Is anybody else going through the same thing? I already have a high BMI (26), but was an active cross fitter before getting pregnant. Is t because I’m not working out as much? I am terrified of how much I’m going to gain. Anybody else experiencing similar, and how are you dealing? Help!