The embarassment factor

So I usually don't post two blog entries so close together, but something happened today that I want to share and see how others have dealt with it.
I am a nurse on a psychiatric unit, and we are required to learn self defense-type moves to keep our patients and others safe. Walking into the training I felt very self conscious, I am the heaviest one here, including the guys. Luckily we had a smaller class so that made things a little easier, and going through the basic grabs felt okay, but when we had to drop to our knees and pull someone down with us, flip them around and put them on their belly while we laid on our sides next to them, I felt very nervous. Just watching my co-workers who I love and trust, I felt like a beached whale, I was sooo embarassed about my size. If felt myself tearing up and the dramatic part of my personality wanted to jump up and leave. What if my shirt came up and everyone saw my fat belly (it did ), what if I crush someone because of my weight (I did), what if I hurt someone, what if I get hurt?  Eventually it was my turn and you know what, I did okay. The worrying about it was far worse than the reality of doing it, and I was judging myself much harder than others were.
Processing this later today I realized that we really are our worst critics. Nobody I worked with thought badly of me today regarding my size, I was just doing a mandatory training for my job. When I spoke to one of my friends about this she told me, "Nobody is judging you" 
But I was judging myself and setting myself up for failure because I told myself that everyone was secretly thinking bad thoughts about me. The reason I am posting this is because this way of thinking sabotages me all the time. I don't do things I enjoy because of being embarassed about myself/my size/my weight.  Thats why  I don't go out dancing with my husband, its why I don't get up and sing in front of people (even though I am pretty darn good at it) Its why I don't follow through with going to the gym or exercising, I feel like people are thinking "God she is so fat, why does she even bother?"
I am not going to do this anymore, I have to be in control of these negative thoughts and realize that everyone has negative feelings about themselves, there is something that everyone hates, whether its their weight, their hair, their complexion, their thighs, we all have our insecurities.
So that is my new goal, I am going to try to push beyond that "embarassment" and live my life.
I CAN do this!