I had marijuana once and i had a bad trip. after that day i have always in my mind those feelings.now i even fear of alcohol. what to do?

No need to use these: No herb or medicine is equally good for everyone; most feel good when using marijuana but it makes some anxious; it's also possible what you had was adultered/contaminated as a really bad marijuana experience is uncommon. But you never need to use it again. Alcohol may not cause anything like that but in excess isn't good for anyone.You could try a single serving to see how it feels or just avoid.