Female masturbation. PLEASE HELP!?

Okay, so ive never had sex so i dont really know exactly what is normal. But when i masturbate i never put my fingers inside of me, i just play around with my clit because i dont feel anything when i go inside of me. i dont want to go up to my gspot because i cant find it. so when i play with my clit i feel good because thats what supposed to happen, but then it escalates to a point for about 5 seconds, this really good feeling for a short period and then it all ends. i stop because i cant keep going because the feeling is overpowering. and when i stop, im not in the horny mood anymore. this whole process is about 5 minutes. i've never came, this cant be an orgasam? what exactly is this? is this normal? what do i have to do to keep on going without having to stop? THANKS SO MUCH.