If you can get methylene blue under one of it's brand names, that's your best bet. Intravenous administration is preferred because it takes effect more rapidly, but since you don't want to go hospital you could consider taking it orally. The dosage is 1-2 mg/kg with a maximum dose of 7 mg/kg so don't overdose on it.
It was even part of a crazy debunked health fad a while back. Amazon still sells it as a disinfectant for fish tanks, for example.
Other than that, maybe filtered water, a few sips, if you've vomited and only several hours after doing that, then drink every 15 minutes for the next few hours. Note I still think not going to a hospital after a failed attempt seems like a bad idea to me, and that failure chance is low if you do it right anyway. Methyl blue won't save you then.