Hi Brittany. It sounds like you are suffering from Anxiety and Depression. It is common to suffer from one if you are suffering from the other. I suffered for years with what you are describing and also refused to go to the doctor or tell my parents. For me the symptoms only got worse to the point where I would be crying for hours almost daily.
I really advise you to go see your doctor and talk to him/her about how you are feeling, they are there to help you. They can give you anti-depressants, offer you counselling, as well as recommend books for you to read which will help you get back to your old self. I really wish I had listened to my friends and seen my doctor well before I did. Ask yourself, "What's the worse thing that can happen if I do go and talk to my doctor?".
If however you need more time there are some great books out there that can really help you such as Overcoming Depression by Prof Paul Gilbert, which really helped me, it uses CBT (cognitive behavioural therapy) which in my opinion is the best and fastest way to get better.
I hope this helps