New workout partner

I just recently got a membership at a gym to get myself to work out more.  I noticed that if I pay for work outs, I tend to actually go. Its not just a gym with machines and weights though. Its a gym with classes and I can go to as many of them as I want.  I go to a fight class on Monday/Wednesday and a pilates class Tuesday/Thursday. When I first started going there I had a friend that went with me.  So during the fighting class I would always have a partner and we would always have a lot of fun. Well... my work out partner ended her membership. So I went into the gym the other day for the first time with out a partner. And of course... there was an odd number of people that day. So I had to partner up with the very strong, very attractive, male instructor! Needless to say, I was freaking out a little. I had to be on my A game.  He held the punching bag first and I was trying my hardest so I didn't embarrass myself. And honestly, I impressed myself. Three gold stars for me! But then we switched jobs and I had to hold the bag. I braced myself as much as I could, but every time he punched the bag it either almost flew out of my hands or it pushed me back way too much.  By the end of each round, we were literally on the opposite side of the mat from where we started. He obviously did not go easy on me. I guess you aren't supposed to go easy on people when you are a trainer but come on man... I am a woman who is 5'1.

Just hoping next time there is an even number in the class.