Yeah, Xanax is used usually for panic attacks and anxiety and for people who are starting anti-depressants as an intermediate step to use until the anti-depressants kick in. I don't know if it is a muscle relaxant too. I think it would be quite strong and could make you out of it.
I think the low dose valium will have a small calming effect and will relax the anal muscle. I don't have any personal experience with Xanax though the FNP I worked for prescribed it from time to time for anxiety for patients who were starting out on anti-depressants.
Well, I think it is too soon to say if you need the metamucil. I would just see how the next few days go. I really like to take Andrew Lessman's Fibermucil supplements. It has both soluble and insoluble fiber plus acidopholis which supports healthy GI tract flora. It has been so helpful in mainting regularity and the right type of stool. I got mine from HSN.com. Yes, the shopping channel! (In my defense I don't really watch it on TV but I do like their jewerly!) He also has a website
www.procaps.com that you can order directly from them.
HTH
Lecia