You're right it has been discussed before. Beaten to death actually.
OK I'M JUST PLAYING WITH YOU.
In order to answer your question, I need to ask a couple of questions.
Is it that time of month? I'm up 2 lbs today from what I was on Thursday. I KNOW I'm due within the next week or so. I also KNOW that I cannot have possibly gained 2 lbs of fat in just 2 days.
Are you drinking enough water? If I miss one day of drinking enough water & get on the scale the next day, I find that I have gained weight--approximately 2 lbs believe it or not. Drinking plenty of water makes your body expell excess water weight. If you don't get enough to drink, your body retains it so that you don't become dehydrated.
Some people would have you believe that you are gaining muscle weight at a tremendous speed. Unfortunately, it is impossible for the average woman lifting even very heavy to gain more than 1 lb of muscle weight in less than a year. That said I don't think it is muscle weight. Unfortunately, I can't find the link where I read that otherwise I'd post it. It is also impossible to lose fat weight & gain muscle weight at the same time.
Re-evaluate what you are doing. If you have been keeping a journal look at what you have done differently within the last couple of days. When was the last time you weighed yourself & did you weigh yourself this time in exactly the same way; e.g. naked or dressed in the same exact clothes, in the morning or at night, same scale?
DON'T get discouraged. I have been stuck on a plateau for 2 years, no gain, no loss. I made some changes to my diet 8 weeks ago & have finally started losing again. During this 9 weeks, I lost 5 lbs & then gained 2 back, I knew what I did wrong & corrected it. I've been losing 1 pound (+) a week again since for a total of 10 lbs on Thursday.
Keep us posted how you do.