Ugh that really sucks your friend reacted that way. Some people tend to do that. Or they go the other route and say "Oh I know all about it since I saw Sybil that one time on Lifetime." /rant.
But yea. That's a really horrible response you got from her. People react differently. I wouldn't take one reaction and assume that will be the reaction of many. In the circle we've told, we've had some people reject us ("RUN FOR THE HILLS!" response), some people accept us except they only accept one of us as "real" ("Well you are all just parts of person-X"), and the rare gem actually accepts us as individuals and doesn't think we're bananas (yaaaaayyyyy the best kind of people!). IMO, it just boils down to their own reception of the idea. I think the bad reactions are more reflective of their own sh*t (narrow minded for one, or triggered, or whatever) and not something you should hold on to, it doesn't reflect who YOU are, it only reflects where they are with this information, and that itself probably has many layers and stuff that nobody knows about but them. Run-for-the-hills reactions do hurt and it is sucky and of course you can be upset about it. I would be. But don't take it to heart for the long run.
As per the T, hm. some are good, some are bad. A good therapist will build you up, a bad one will do the opposite and then leave more knots to be untangled. in fact, my rant up there could be applied to therapists too... anyways, if you ever decide you want a T, my 2 cents is - look around online for people who are part of the ISSTD. look up Ts from their website, i know they have a "find a therapist" place. Or roll the dice and visit local Ts. even if one knows squat about being Plural, if you find one that you click with and he/she is willing to learn and go on a therapeutic adventure with ya, that's good too.

But if it's not working, if it makes you unhinged, or something is fishy, or it seems like everything is worse, remember to take care of yourself - if that means leaving, go. I have met some folks who got a lot out of therapy, but we've never had much luck with therapists. we do most of that for each other and it's worked out fine. check in with yourself(/selves). for some people therapy has been miraculous so it really just depends on finding that really really good therapy relationship, i guess.
and this forum is totally here for you. none of us are going to run away screaming and thinking you're nuts. Welcome