First of all, I think that you are really brave to share this. I completely understand it, I've done similar things and felt horrible for doing it. The feelings of guilt and shame are always behind these actions because we know where these 'undesirable' impulsive actions come from. It is completely normal to feel frustrated and envious of someone who is in a 'better' position than ours (and where we want to be), however, to a certain degree.

That's why when it exceeds to a point that bothers you, I believe that the way out is to seek for help, be perseverant and persistent. What is done is done, but perhaps when you feel more comfortable you may contact your friend and be really open about it with her. If she is someone who is meant to be in your life, she will understand. For now, I wouldn't try to 'force' yourself to be highly social and pretend to be fine with certain situations, for that will only mask the issue. It takes a while, one day at a time, but things will get better!