This was what happened to me last week, I had to beat up a bigger thug bully. He was strong, I can't use my kicks since I can't see my range without eyeglasses, so I just grabbed him by the leg, he resisted and I use all my energy to put him on his back and rained punches to his face, he then gave me his back and I choked him, with so much blood all over coming out of his face cuts.
If it comes down to it, don't think, just defend. I get intimidated too, but I will just trust my instinct and protect my face during the fight. You have MMA skills, that's awesome, you're winning the fight most of the time.