Regret is something that's worth keeping in mind as we're thinking about choices.
When we make a choice (either because we have to make it or because we want to make it) we can later look back and regret what we chose (that's the very simple version of regret- in real life regret can be a more complicated proposition).
PTC, I understand you feel that incredibly strong need to cling to your current weight. It may be though that you end up regretting the loss of your relationship with your therapist.
Regret is a hard one. It's painful to feel. It's this weird combination of sadness and longing and a desire to go back and do things over... (someone more poetic than I can probably do a much better job of describing regret!). My personal strategy is to try to avoid encountering regret as much as I possibly can!
Yogini, you were writing about missing your eating disorder (and I echo everyone else's welcome to posting in our friendly little community!). When people make those hard choices about changing their relationship to the ED there is inevitably "missing the disorder" involved. "Missing" the illness is not easy to feel. Not at all. It's also very normal. And... the really good news is that the kind of missing it is does not involve regret.
You were also describing resorting back to the ED behaviors when discussion about body image triggered a lot of intensity for you, Yogini. Defaulting to those ED coping strategies when someone gets overwhelmed or overly stressed or triggered is not a failure. It's simply what you've known to do to cope. It is familiar- and we tend to resort to what's familiar when we are under stress.
Your job now is to rely on all those cool support people you've found, and work to not let yourself slip too far back into the disorder (because you are so right about how fast the ED can cascade back in and take over).
There are obvious reasons you'd want to not slip too far- like not wanting to risk your health, not wanting to have to give up activities if you become weak... Another reason you will want to try not to slip too far now is that the more someone slips back into the relationship with the ED the less connected he/she is to herself and to others around her. And, you know what? Not only does that feel awful (lonely and isolated for starters!), it can cause regret!
And, you guys know my feeling about it: regret is something we want to try to avoid. Hey, that's a decent Bumper Sticker...