Hiya babe
im very conscious about gaining weight but what you have to remember all ur doing for the first few days is eating, and not moving, so your bound to put on a little weight as well as retain water (i was terrified of going toilet for ages so i had alot of water weight)
once u start moving around i suggest going for a little walk around the garden or up and around the road, jut to get all the food uv eaten digesting and moving properly, hope this helps babe 😀