The little beating device i had to use in my horse lesson today?

No it's okay if you didn't over- do it. The horse is probably just testing you. If you are new to riding and not confident in the saddle, your horse can feel that (what a connection, right?) lol. So, I wouldn't worry so much unless the horse your riding has another underlying reason why he is't responding to your command. Maybe he has a past injury or something that is causing him discomfort? Well I bet that isn't the real problem though. I'm guessing he just wants to test you so don't be afraid to use the crop as an aid in the beginning until your horse realizes you have confidence and are ready to be a leader. Once he starts responding, then you should forget the aid. Use it for now though if needed. =)