I've had a sudden surge in unexplained weight gain over the past couple weeks, going from around 51kg to nearly 58kg in a matter of a month without explanation. I'm eating exactly the same as always, and have even been working out more than ever before, doing minimum an hour at the gym everyday. Just this week I gained around 2kg. I used to be overweight and it took many years and hard work to get to the weight I am now, and do not want that to change! Someone please tell me what this could be!