Do you ever feel like those around you attribute your every mood to being bipolar, and no longer take you seriously when you are genuinely upset or mad?

Only one friend knows about my moods, (not diagnosed for many reasons, mainly the fact that I don't want to be labeled and the thought of facing my moods head on scares the crapola out of me)
As I mentioned in the other thread, she was at my house the other night, and I had extreme hypomanic laughing fits, to the point where I left the room because I was literally on the floor, tears streaming down my face, hands and feet banging in hysterical laughter for absolutely no reason. And twice throughout that i felt like crying, and had to fight back tears. Afterward, I went into anger mode.
Today, my friend's crush who has been relentlessly and obviously leading her on, was extremely cruel to her, telling her "I don't date men" to the dismay of everyone who was convinced he really liked her. I wasn't there, but when I heared about it I was absolutely enraged. I've been in a stable mood today, so I was genuinely mad. Apparently she didn't want to tell me about it, and when she found out I knew she was mad at the person who told me, and was extremely rude to me when I tried to help. We usually stop in front of my class and talk until the bell rings, and today when I stopped in front of the room she said bye and kept walking. I was so mad at her because I was so worried and mad for her, only to have her treat me so rudely. On the bus I learned that several casual friends knew about it, but she didn't want me to know, and she was passing notes with a girl who doesn't even like her (and often talks about her) but she refused to let me see. When I tried telling her I was mad, she wouldn't even let me talk. I kept telling her to let me talk, and she wouldn't, so I raised my voice on the bus and yelled at her to listen to me. There were only a few kids left (all friends of ours) who of course went "Ouuuu" and she said "Oh, don't worry. She gets mad like that a lot. trust me, just ignore it." I was completely dismayed by that- she was completely invalidating my anger towards her because of my irritability. I was genuinely mad, not having an episode! She was being extremely rude to me, and refusing to let me talk, and then she completely invalidated my anger by saying to just ignore me because I "Get like that a lot". My response was "No, try NOT, you're completely wrong" and she cut me off mid sentence by turning around and talking to the other kids saying "Yeah, trust me. She gets pissy like that a lot, just ignore it" I couldn't believe my ears. The one person whom I ever trusted, and there she was, completely and blatantly invalidating me, even in front of other people. I said "no, you're wrong. I'm mad at you becasue you are being rude and a ******, not because of any other reason, so stfu!" and after a few minutes of silence, she tried talking to me like nothing ever happened. I don't even know what she said because I just kept interupting her saying "Okay. Okay. Whatever. Okay" in a "I don't care, just shut up" tone.
Her x-best friend was on the bus, last year she got fed up with her and stopped talking to her all together. After my friend got off the bus, she told me that she knows exactly how I feel because my friend did the same thing to her all the time, and she stopped talking to her because she was about to explode at her. She advised me to do the same- leave the friendship peacefully enough before I completely go off on her. I have no plans of even speaking to my friend tommorow. I feel so utterly betrade. I confided in her what I hide from the rest of the world, and now i feel like she thinks i'm incapable of having normal emotions. That if I'm mad, or sad, or whatever, that my feelings should just be ignored because my feelings don't matter- I don't matter, because I'm bipolar. how am I supposed to trust people if once they know, they are just going to write off any feeling I have as me just being crazy.

Sorry for the long rant.
Do your close friends/family ever just invalidate you and how you're feeling all together? Like it doesn't really matter?