Calm down, Hiro.
Anyone who makes fun of anyone else for frequenting BlahTherapy is a heartless bastard. Remember that your peers are teenagers, and (if I can rightly extrapolate your ethnicity from your name) your culture looks down on mental "deficiencies", but you have to keep in mind that cultural opinion does not dictate truth, and BlahTherapy is not a dirty little secret, so you have nothing to be ashamed of.
Your brother and everyone else's opinion of you has no bearing on who you are, and anyone who would make fun of you for having troubles and seeking help is not the kind of person you would ever want in your life anyway, so if anything, your brother has done you a favor by lighting a beacon to help you identify the people in your immediate social circles who you want nothing to do with. Count it as a way of identifying the bad people around you.
Just breathe slowly and deeply until you calm down. Peer pressure is basically irrelevant; words only hurt as much as you let them, and short of someone putting their hands on you, you have nothing to fear.
You have people here who absolutely have a positive opinion of you, and will never judge you, just because you can't see the faces of your supporters, it does not make your detractors more "powerful".
If you view this negatively, it will impact you negatively. People finding out that you are on BlahTherapy is not worth suicide. Getting help is not shameful. The shame is on the heartless bastards who lack empathy, humanity, humbleness and compassion and are capable of socially ostracizing someone who is only guilty of accepting that they have a problem and openly sought help.
Do not view yourself negatively for this. Let this event give you clarity about the nature of many of your peers.
If you want to discuss this further or if you feel you need to talk, my inbox is always open.