well, gaba will not work for you, it does not go across the blood brain barrier. there is something called PharmaGABA, which is made naturally from kimchi, will work better. I've tried it, it may be calms me down a little bit, but didn't notice huge differences. still you should give it a try to see.
GABA is waste of money, won't help you.
try wild herbs from the nature instead, such as valerian, st john's wort, ashwagandha, and eat it raw or dry it. you could eat even raw cannabis leaves.. it's natural herb, non toxic, and does not do any harm. or you could try black lotus, or try even growing stuff your self, buy seeds