Gaining weight fast and metabolism?

I recently began seeing a nutritionist to help me recover from an eating disorder. She has been increasing my calories by 300 for the past few weeks. I'm currently at 2,100 and have been at this amount since Saturday. However, in less than a week, I have gained two pounds, gaining one pound over the last two days. Is this possible, or could it be water weight or something like that? My stomach does look a lot more bloated. Also, I don't think my metabolism has started increasing yet because I haven't experienced night sweats or weight loss, like I know a lot of people experience when going through this. Why isn't my metabolism catching up yet? Will it ever will?