Do I fix the teeth? (this is kind of long sorry but I need help)?

Okay so here's the deal. I went in for my regular 6 month dental check-up today. After the lady got done cleaning my teeth and everything she said my teeth & gums looked great I have done a wonderful job brushing. So then I sat for a little bit waiting for the doctor to come in and check over them real quick and he was some new old guy. He was REALLY weird my mom even got creeped out by him. But he started off telling me he was going to cough and then he started digging in my mouth. He ended up saying I have spots/cavities on 5 of my teeth. He asked how long it had been since my last cavity. I'm 16 years old and have never had a cavity. How could he not be able to tell that? He had my records and mouth right there. So then he began questioning me on everything I said. He said pop is a major factor in kids my age. Well I don't drink pop. He said candy and I told him I don't really eat sweets then he says sweets aren't really a big factor in this. Then why did he ask about candy if sweets don't matter??? And he just kept going on about how something I'm doing has had to change. NOTHING HAS. So then he went to check my mom's teeth and kept asking her what I have changed and he even asked her if I have had a cavity. I don't get it. He didn't believe anything I said and I guess he just sat there with my mom saying I have had to change something over and over. Then my mom flat out said I can't take a shot for the cavities and he asked her three times why I couldn't before my dentist came over and said I was shaking the entire time and I can not take a shot. This guy was just a nut he even told me to sip my milk and then drink water after because that could be the problem! I'm supposed to go in and have my cavities fixed obviously, but I'm really hesitant. I want to get a second opinion, but my mom's insurance only covers every six months so I need to find one with free consultation and I don't know if we can find one. Does anybody agree that things don't really match up? Should I just go in and deal with it or do I wait until somebody else can look??