Trying to lose weight awaiting a medical diagnosis

I'm sorry you are going through this. I don't know how I would handle that. It's good that your doctor wants to investigate thoroughly.
Some things to consider are
Go back to weighing and logging your food today
Don't bring any food into the house you don't want to eat. As odd as it may sound, I like those mall baby carrots because I get the satisfaction of chewing and munching while keeping calories low
Try different kinds of hot or iced tea. They can offer a satisfying taste without calories.

Does the doctor mean "no vigorous exercise" or "no movement"? There's lots of activities on that spectrum.
Take short walks a few times a day if that's allowed, even if it's only 1 block
Look into "sit and be fit" type exercises that are not vigorous. These and walking will give you something else to keep your mind busy and will help you feel better too

Consider a hobby that occupies your hands and your mind like drawing, painting, knitting, beading, woodworking etc. You don't have to be great at it, just have fun and you might find a new passion. You might be able to take an inexpensive class in the community College or parks/recreation system.

Wishing you the best,

Part of your 7 pounds is likely to be water weight and slightly higher average digestive system contents, not fat. Additional carbs require a little more water weight as they're being metabolized, and that will drop off within a few days of returning to your normal carb level (which needn't be low, BTW, just your normal). The higher digestive system contents will drop off a few days after your eating consistently returns to your previous routine. Then you'll know how much actual gain you have . . . but I'm betting it's not the whole 7 pounds.

I'm a survivor of stage III (locally advanced) breast cancer . . . 17+ years ago. I can understand the anxiety associated with biopsies, tests, waiting for results, etc. It will be hard, but you will get through this.

It's easy to sink into a sense of anxious panic, falling back to frantic pursuit of bad habits that provide a bit of distraction, but no true comfort, because I know at heart that they're not my best self, that they're ultimately working against my interests, my health, my happiness.

This a time to be kind and generous to yourself, to give yourself what you truly most need. Indulge in some activities that usually bring you calm and joy, then let yourself settle comfortably into those positive feelings, and help anxiety slip into the background for a time. It will take effort to do this, but you can. Be firm with yourself, but gentle.

I don't know which specific things work for you, but some that have worked for me are gentle stretching, simple nonreligious meditation (http://www.relaxationresponse.org/steps/ ), aromatherapy bubble baths, being outdoors in a "quiet" place where I can listen to sounds of birds and breezes, comedy movies, time with close friends, phone calls or emails with far away friends/family, visiting gardens (greenhouses/conservatories in winter ) or museums, listening to happy music, diving into neglected hobbies (mostly crafts).

When I was going through treatment, it helped me to think about, even write down or make drawings/collages about things I'm grateful for in my life (fortunately, they don't have to be good collages or drawings - I can even throw therm away after; it's just a way to immediate immerse myself in those thoughts).

There will be bad, panicked moments, maybe some less than ideal actions. It's OK: You're in a difficult place. Just gently, kindly bring yourself back to positive actions as soon as you can manage. You will get through this. I'm hoping for an "all clear" on your tests, but either way you can and will make it through what comes.

((Hugs!))