I need answers plase?

over past few day my weight been going up down staying the ame etc i only sleep 2-3 hoursa night n i eat healthy anyway i eat my dinner at 11 pm had snack a 4am when i woke its now 7am.i went ya know ppop and piss i steped on the cales i gained 0.3?! could it be that lack of sleep why it went up(but dint acautly gain) or i could still have food in there?or did i just gained weight?and does it go down stright away or doe it take time?thanks also will takeing multi vitamins make me gain(i stoped takeing them cos my brother said they do..) thanks