M.,
I haven't been there, but I've heard quite a few stories of people getting pregnant soon after an HSG. Apparently, sometimes just the procedure "clears the way" a bit (think, unintentional roto-rooter) and can make a pregnancy more likely for a few months. This might be why your doc is recommending the clomid for a few more cycles before taking further action. A single tube shouldn't increase the risk of an ectopic, but the scarring in the other one can...if an egg gets caught up in the scarring, but still gets fertilized, you have the risk of that complication. As for the appendectomy, the scarring is an unfortunate complication, but it can happen (and re: suing any docs over it...it won't work. If you look back into the informed consent you signed before you had it done (pain meds or not) it will surely mention possible scarring and adhesions. Anytime you cut into the abdomen, you risk the formation of scar tissue in surrounding areas, even if they weren't directly affected by the surgery. Sorry...not the news you probably wanted to hear.
Finally, a second opinion never hurt anyone! I'm all for second, and third opinions, and I bet your doc would support it too. Is your doc an OB/gyn or a fertility specialist? If a general OB/gyn, I'd get a referral to a good fertility specialist and while you wait for that appt. continue on with your current plan.
I hope the HSG not only found the problem, but gave your body a boost and your next cycle gives you a wonderful blessing!
I'll be praying for you!