green come on now mrs. You KNOW in that short a space of time you haven't gained 4lbs of fat. You KNOW that.
What you've done is refilled your glycogen stores and retained water with the carbs, that's all!
From all the walking you've probably got some muscle tissue swelling in your legs too which will add weight.
Go back to strict bootcamp for a week and you'll be back to normal.
In terms of going back to eating 'normally'... well duh, of you eat like you did before you'll get fat again, that's how you got fat in the first place.
However, it doesn't mean you can't eat carbs in reasonable amounts, you just need to find how many carbs you can have before you start to actually regain weight. Remember, when we talk about weight gain we're talking about fat not water and glycogen, so allow 2% for those before you judge your weight as having increased. So increase your carbs a bit for a couple of weeks. If you maintain your weight you're fine. If you gain you know you're over your limit and need to cut back and if you lose weight you need to up it a bit.
People don't naturally maintain a stable weight 100% of the time. You usually have a 5% fluctuation zone which you stay within generally. Find out what your 5% zone is and if you go over that, just go back to bootcamp for a week to get back in it.
People regain weight after weight loss because they treat it as an achievement not as a lifestyle change. Yes, weight loss is an achievement but by far the greatest achievement is changing your lifestyle to the point where you can maintain that loss.
Chin up mrs, you're fine 