Anxiety getting worse. What do i do?

I've had anxiety since I started high school (7 years ago). It's been getting worse over the last 2 years (not that I'm out of school). I seen a doctor about it, but he said "you're just shy, you will never be outgoing so don't try to change yourself". How I feel isn't just "shyness". I have panic attacks, I constantly feel nervous, sick, exhausted and shaky, my body goes numb and I have diarrhoea when I leave my house. I can't sleep at night because my brain goes a mile a minute, my mouth and nails are constantly sore and bleeding because I chew the crap out of them without realizing. I can't do normal things like answer the phone/door, order food, eat in front of people, I can't be home alone without being terrified, I check things a million times (doors locked, oven/stove is off), and have recently been just feeling really sad and depressed. I'm terrified to see another doctor, I don't want to be told that i'm just shy or overreacting again. What do I do?