I need some help guys! Please help!?

In my opinion, you should talk to him tomorrow. Ask him for his reasons for calling you gay and tell him how you feel about it. Maybe you can fix things with him so that maybe things will go back to normal. If it turns out he still calls you gay well then that shows his true colors. But things might not be as they seem. Have you actually heard him call you gay? Probably not. Are you sure that the friend that told you your best friend said that you were gay telling the truth? Maybe, but he/she could be lying for certain reasons. Think things through carefully and decide how you will approach this topic tomorrow. Hope I helped. Goodluck. And also, be who you want to be, hangout with who you want and don't let peoples comments affect you and your life. You're a great person no matter what.