Is it normal to have self-destructive thoughts because you're a little overweight?

Okay, I know it’s not “healthy” but am I the only one with a fragile enough ego to have very negative thoughts because I’m 10–15 lbs more than I’d like to be?

I needed to buy a dress for an upcoming event and today I found my 6” foot tall self in a Banana Republic dressing room practically in tears because I discovered I could no longer squeeze my ample hips and thighs into a size 12 dress. It was all I could do not to hyperventilate in anger when I realized how much I’d let myself go this winter and that nothing—literally NOTHING in that whole damned store—was going to make me not look and feel like a whale.

Now this is a struggle I think many women can relate to, but what concerns me is that in my state of being upset and disappointed,I found myself having very dark thoughts about myself that go beyond just carrying a few extra pounds. Things like “My partner probably thinks his skinny ex was hotter.” (He’s never indicated this in any way, shape, or form.) and worse yet, “I deserve to summarily executed for being such a worthless cow.” and “I would kill myself but I should lose 15 pounds for the autopsy.”

I swear I’m not crazy and these are not daily thoughts for me. I have no intention of harming myself ever and I am currently on a diet so I get down to the weight at which I feel good. But am I seriously damaged and deranged to be having such nasty thoughts about myself?