Lack of social skills leading to my depression?

I’m 19 years old, turning 20 next month and I completely missed out on all those social skills that I was supposed to learn as a child. My lack of social skills continues to hinder my life. Whenever i try to connect with people, they don't appear to be too interested in furthering a conversation due to my awkwardness. I don't know how to act in social situations. When i ever i speak, people tend not to understand what im saying due to my poor sentence structures and i always stumble on words and have trouble expressing my opinions in words when communicating with people. Due to this, i just try to avoid social gatherings as much as possible in college. When i had to give a presentation, my hands were shaking uncontrollably and my heart was pounding so hard. Lets just say it was an awful presentation :( Even in the dating world, i cant seem to get any guy interested in me, my last boyfriend used me and dumped me which led me into further depression. Its gotten bad that i just dont have any pride in my appearance since im just not pretty enough compared to other girls he's dated. Some people tell me to engage in activities that get me interacting with people but i feel it isnt possible since im studying for my nursing degree meaning no time to join other clubs and socialize. Its a tough program and im always studying 24/7 and i dont have any friends to connect with. I won't even have my summer off, I'll be studying throughout since i applied to college in january instead of september. On the other hand, my parents are over-protective and are always keeping an eye out for me. I feel like when i move out one day, I won't have the necessary skills to function as an independant person because they have always treated me like baby girl; they always do everything for me. I deleted my facebook because i dont have anyone to interact with and it makes me feel worthless:/ I dont know what to do anymore