Hi Ann
Your GF sounds to me like she is making excuses to avoid doing this for some reason. What those reasons are seem very obscure especially under the circumstances where you have done so much for her. One positive sort of thought I had is that she might be (in a very strange manner) trying to do you a favour. If you can learn to do your own injections and get over that fear you will be doing yourself a good thing. I never ever thought I would be able to do it but I am so at ease with it now. I feel like I have more control. (Initially I had to do it because my DH turned sort of green at the idea on the very first morning despite stabbing the trial rubber thing when we were being taught really well).

On the other hand maybe she is one of those friends that always takes and doesn't give back much. I've had a few of those in my lifetime! Not any more though...

I don't think you are overreacting - it must be very confusing and upsetting to be let down like this.