Mixing downers, please help

Hey, i just took 15mg of IC-26. i have 0 tolerance to opioids and one time took 40mg oxycodone and threw up so much. i really dont wanna get nauseous and im having anxiety. i know mixing benzos and opioids is bad, but can i take 10/5mg diazepam and some benadryl to help the nausea? thanks so much, any advice is welcome. im stressing. sorry