Other than covid (i had 5 tests @4 diff places & all negative), what could cause distorted taste & smell (a lot of foods smell & taste foul, lotions & soaps smell terrible) along with severe headaches & nausea/vomiting? has been occurring a 4+ weeks?

One possibility is a sinus infection with blockage of mucus in some sinus cavities. Did you have a headcold.that preceded your current symptoms as.sinusitis often follows a heavy headcold that lingered. It could also explain your distorted smell& taste. You may need treatment for sinusitis& measures to get sinuses draining mucus. I recommend consulting an ENT specialist for evaluation& advice.