Go and talk to your personal tutor - I know its still holidays, but he/she will be at work, so give them a ring and either go and talk to them in person, or just explain your worries to them over the phone. If they arent available, then go and talk to a Student Counsellor via your University's Heath Centre/GP Practice, or even your GP. If your Uni has a Nightline service, phone them now. You are clearly very muddled and unhappy, and you need to get some help to see your way through it.
Feeling overwhelmed at Uni isnt that unusual - and it is fixable.