If you were clenching your fists it may have caused your hands to go numb.
I agree with Annie. Use lubricated condoms. If that's not enough you can buy a water based lubricant at the drug store. It's safe to use with condoms.
Don't know why your hands went numb. But if you are not stimulated, your vagina will not relax. If you are nervous, it is not going to feel good. Were your condoms lubricated? That will help.