Frankly, you're gonna get a lot of advice in this thread, when what really needs to be said is 'good job'.
What you're doing is obviously working for you, so I'd say keep doing it.
It does sound like your current diet is a short term medically prescribed thing thouh, and eventually you're going to have to go back to regular food. Again, you'll get lots of very detailed advice on how to do that. I won't add to it, I'm no nutritionist. All I will say is to choose a regime, both diet and exercise, that you can sustain. Extreme diets with complete block on entire food types etc - they work for really dedicated fitness people, but that's not everyone. They can be dreary and boring and painful and unless you're supremely motivated or fitness is a major focus of your entire life you'll eventually have a downer couple of weeks at work or in your personal life or something and fall off the wagon.
Consider taking it slow. Obviously you've got medical reasons to lose a lot fast now and that'll give you a nice start, but when you get back to a non-medical diet, don't deprive yourself. Eat sensibly rather than thinking a psycho grilled-chicken-breast-and-salad diet is your only way to salvation, and don't beat yourself up for to grabbing a pizza every so often (it's NOT 'cheat' food, it's tasty stuff that's perfectly ok to have once in a while)
It's very easy to reduce the calorie content of most modern people's diets just with a bit of research into healthy eating. It's very easy to be a bit more active and burn more energy. The hard part about weight loss is keeping it off in the long term. To do that, you have to design your long-term lifestyle to suit, and that means being realistic about yourself. If you hate your life without pizza, you're simply not going to stick to a pizza-less diet. A slower improvement that stays is much better than a crash diet that has massive visible effects in the short term, but which you won't stay on. The long term is what matters. Keep it in mind. Focus on changing your habits and your routine in a sustainable positive way. If it takes a couple of years to get to where you want to be, that's ok.