I'm sorry you're having such a go of it with this MS and your initial Avonex injections. ThisIsMS is a community of caring people, and as Arron frequently says, "You're among friends."
I hope you won't feel totally alone for long.
Personally I do not think it will do you any harm to miss an injection while you and your doctor are trying to determine what is happening and I don't think the side effects will be that much different if you miss a week.
I have been on Avonex for about 2 1/2 years. I believe, and my neuro does too based on his 20+ years of treating people with MS, that Avonex can indeed make MS symptoms worse for some people. I think it will be important for you to try and determine if you might be one of those people. If that turns out to be the case, there are other options to consider. Sorting it out early may help.
Hopefully you will great a break from this crap soon.