OKay, this may sound a little silly but after losing two pounds I am terrified of regaining the weight. Am not on any sort of restrictive diet but today I had a huge slice of chocolate cake PLUS was snacking on m&ms all the way home.

One part of my brain is saying 'its fine, its just a treat' and the other part is demanding I start exercising asap. So how much 'treats' is considered just right and how much is too much? Am I overreacting?

Well this is probably not what you want to hear but personally IMO a huge piece of chocolate cake and M&Ms apparently more than just a few is not an acceptable "treat" and will make you fat again really fast. However, if it is just one day you did it you will be okay; it's just blowing it once and not that big a deal. However, if you make a habit of it, you won't lose weight. BUT again... it's just one day and it is done. So don't beat yourself up over it.

Ok, you asked- so I am giving my opinion.

Itīs too much chocolate and/ or you have a problem with your relationsship with food if you are asking yourself "Was that too much?" after you ate it.
I guess you already KNOW, that it was too much....

But at the moment itīs done, itīs over and itīs past. Try not to worry too much about it, start new- and be aware next time.

Just about all of us do that. Well, I've been guilty of the chocolate incident anyway. (especially ice cream). Unfortunately, these woman are 100% right. Yes, it was too much, and yes it will throw a wrench in the wheels of progress if you keep doing it. The good news is, it was a slip up and we can always get back on our feet. I am sooo feelin' ya on this. I have an unhealthy obsession with chocolate and ice cream. I sometimes think it would be for the best if I could take a vow to forget it exists.

A good rule is no more than 3 bites of treat foods like cake and candy. And only one choice in a day. Food is not a treat when you have big portions often.