I can relate to most of the thoughts on this thread, and have experienced the really negative downsides in the past and with loved ones.
Suicide in my opinion (and others?) doesnt make the misery end - it shares out amongst everyone you know, the closer they are, the more they get... There are so many things you havent seen or done yet - caves, climbs, beers, steaks, swims... whatever!
GP's are a good first contact for professional help, but bear in mind treatments can take a long time to kick in, and medications may need tailoring to you. 28 days may not even scratch the surface. 3 months is typical for a proper clinical effect to take hold, and coming off should be done under advice as well - not a sudden cessation but a gradual weening off.
Specifically for those with an immediate urge to harm themselves, try a cold thermal shock - stand in a bowl of cold water, hands under the cold tap, stand outside in a T shirt in winter until you are chilled. I dont know why but this seems to reset your mood for a while. Getting outside - walking, cycling, whatever, also helps...
Reaching out here can be of benefit as many use pseudonyms, so a negative feedback in the real world is not possible.