Emm, I know exactly how you feel. At this precise moment in time I'm ok with the extremely limited diet but I've been very frustrated before and am quite certain I will be again. It is especially frustrating when you are reaping any benefits from it. I did have some improvement with the diet alone but still not enough to feel it was worth all that I was giving up. What I have found to make a significant difference is probiotics. I was taking one called Udo's Choise super bifido plus which I purchased at my local co-op, it's $90 for a 30 day supply but I did quite well with it. I'm currently taking Align (samples I got from my GI 3 days ago) it's too soon to know if this one will work or not.
I wish you the best and hope that tomorrow you find a renewed courage to stick with it, and possibly try something different.
-------------------- Jeanette IBS-D, then switched to IBS-A, now stable with Udo's Choice Super Bifido Plus Probiotic