I agree with mofetathat this may be cannabinoid hyperemesis. Most articles I have read on this syndrome state that the symptoms will go away after the patient abstains from further cannabis use. If you have more episodes of nausea, chills and vomiting, you may have to discontinue all cannabis use to gain relief including discontinuing the use of edibles.
An interesting associated finding with this syndrome is that most people suffering from this problem find relief temporarily by taking hot showers or baths. Many of them reported taking multiple hot showers a day! I wonder if the OP finds relief from his symptoms in this way...
The low heart rate and chills could also be associated with chronic cannabis abuse.
I would bet your doctors put you on antibiotics because they didn't know what else to do. Not sure why it made you feel better either...
I hope you feel better,