Hang in there! Like a previous post said - even if you're not seeing the weight changes you want (yet!!!) you're a still making healthy steps! The weight sometimes is slower to change while your inner body is healing.
I also agree with another previous post - ask about seeing PT if it wasn't specifically restricted yet (yes, every case is different) I had some back issues, and my doc gave me 3 different pills to take for it. He didn't even mention PT. When I asked if there were non-pill solutions that I could look at (either in place of pills, or just to go along with them) he actually rolled his eyes and said, "oh, you're one of THOSE..." (needless to say, I didn't keep going to him when he made me feel like there was something wrong with wanting to do more than just pop pills.) But only then did he make a referral for me to go to PT.
I'd also look in to yoga when you're able to - of course talking to your health care team first :) But if you get the right teacher, you can do very simple, low-impact things. If you have a good teacher, they'll be able to create programs for you based on your current situation. Maybe you've seen it circulating the web, but there's a very inspiring story of a disabled war vet who had both legs in braces, and had to use crutches to get around. But he found a great teacher who helped him heal. veggiekate.com/2012/05/30/from-300-pounds-
And definitely make sure you're working closely with a dietitian, and getting good nutritional supplements. A diet less than 1200 calories won't provide the nutrition you need, especially if you're healing. Sometimes weight loss will stop with too low a caloric intake because you don't have the proper nutrients for the metabolic processes in your body. So if the doc prescribed such a low intake, you need to be sure you're getting your nutrients from a good set of multivitamins or other source. Talk with the doc and hopefully a dietitian about it!
What is it that limits the speed/distance when you go out? Pain? Mobility of joints? Breathing? Muscle strength? Perhaps if you have trouble doing cardio type activities or lower body activities, you can focus on strength training - some arm weights?
But keep at it :) Slowly crutching a short distance is still leaps and bounds better than doing nothing!