Apart from going to the doctors which I hope does help for you as they have a lot of connections, I think you should go see whoever is in charge of the quality of student life at your college. They should, firstly, be able to talk to somebody who can hopefully help you, you should also tell them about your biology tutor. She does not sound professional in any way and definitely doesn't sound as if she is helping your situation.
It's natural to feel low and emotional at times but as I'm sure you know, the length of the time that you have been feeling this low isn't healthy and you should seek help from as many different places as possible. Doctors, mentors particularly for the quality of student life and maybe even a counsellor which most colleges offer or have connections to if you feel that this would help.
If you are experiencing problems and feeling emotional over certain things then just try and think positively about them? I know that is not easy so try and talk to your family and friends about how you're feeling.
I hope things get better for you and if you need someone to talk to as you're feeling lonely then I'm always here to help anyone who needs it.