Hi Rebecca,
You have been dealing with a lot of pain and I feel for you. It is tough to please your parents and cater to their every whim. Coming from a very tightly knitted family, I can understand the need to seek approval from your parents. Both my parents constantly criticize my unconventional approach to life. Yet, I find that they only do that out of their fears and their insecurities. Their fears should not seep into your life to the brink of making you miserable.
I had the issue that you are going through when I entered college. Three years later and much turmoil, I realized that my parents generally acted this way due to them being insecure and uncertain about the things they could not control. It was at that realization that I accepted that I cannot please my parents every time. At the end of the day, there was going to be some disappointment along with approval.
You cannot please everyone. It is a grueling task that puts you in a precarious position. What I can say to you is that you should think and believe in yourself. It is not an easy task. This will take some time to develop a sense of self-confidence and the way you can start is by doing things. Confidence is not the ability of displaying your success to others, but the ability to recognize failure and the need to always improve to others.
I hope this helps.
Vinay