All I can say is keep fighting.
My grandma had cancer, and after the loss of her breasts and many years of suffering and fighting, she won the battle.
She had a pretty severe Breast Cancer, yet she is still alive today.
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If people don't want to be your friend because of your "mood swings", maybe they shouldn't have web your friend in the first place...
If they don't understand your changes in personality, and that the underlying reason is not your fault, then they weren't good enough for you to be your best friend in the first place.