but since then i have gained weight even though i have been watching what i eat and stuff.
Clearly you haven't been watching close enough
Seriously though its easy to gain weight pre op, you're not alone in that. However if your surgeon stipulates that you have to lose weight before they will put you forward for surgery then you run a grave risk of being refused if you don't do your bit.
If they told you to lose weight then they are doing this usually for two reasons, it increases your chances of survival on the table, and it allows them to measure your commitment to making this work. They invest a great deal of time and money in us and if they don't believe we are worth the investment, they won't go ahead. You could say why should they
How much have you gained? by reducing your intake by just 500 calories a day you can lose at least a pound a week, and probably more than that in reality. So if you're seeing them in March, you could lose half a stone without too much effort. Just cutting down I lost 55lbs on my run up to surgery
It's really up to us to do our bit to help them to help us. If you're committed to getting approved you'll find the strength and resolve you need just like so many here have done before you. If you're not then maybe now is not the time for you. It doesn't mean you'll never be ready, just not right now
Good luck with it, and I really do mean that, the people here can give you trite platitudes and sympathy because we can all sympathise with your position. But when push comes to shove it's what you put in your mouth that will determine the outcome. Again very best of luck