Hsg test

I have a hsg test later today, and I can't sleep I'm sooooo nervous!! we have been trying to conceive for almost 2 years. I've done 8 medicated cycles (currently on 9th). And have done 1 iui, and doing another one this month. This will be the last round with medication the doc said I could move on to the shots. But I'm terrible with needles, I guess I should be worried??? anyone here done the hsg test? what should I expect, is it painful? what happens if my tubes are blocked, the know what? :/