Rachel, I feel your pain.
I am very fortunate that my friends have supported me like crazy, but I recently felt so let down by a business associate/friend that I had a little temper tantrum which is quit unlike me.
We had an agreement to support each others businesses but I have been left feeling like I am doing most of supporting, promoting etc...
I had quite a bit of resentment come up around me feeling like I am always being mindful of supporting this friends endeavors when ever possible, even creating the opportunity to do so, and feeling reciprocation has been conditional. I suspect that it is around approval in how I am running my business.
I took a step back and realized that as Dan said the voices I am going to pay attention to are those of my customers and others, including my new biznik friends who have thoughtful constructive input, AND who are alright with me saying that their advice fits, or does not fit.
I am sorry though, I understand how bad this can feel and wanted to tell you so. I am out here as well if you are looking for a supportive voice.