Exhaust fumes symptoms and conditions

I was prescribed a generic for keflex (cephalexin), 500mg three times a day for 10 days for cellulitis(skin infection through an insect bite). My gastrointestinal tract went totally haywire as soon as I started taking the medication, bad stomach upset. The infection subsided in a couple of days but started having stomach cramps and the diarrhea continues for almost a month till I started taking probiotics to replenish all the flora in the gi tract.
It has been almost a month after I stopped taking this medication and now experience phantosmia( phantom smell ), in my case smelling smoke/exhaust fumes at random times throughout the day. I mentioned this symptom to the doc and according to here, it is one of the side effects asked me to hang in there for 5 more months before I can consult an ENT specialist.