Hi rabbit hockey,
you recieved some very god advice and support so far.I also think you're very brave for taking the step in seeing your doctor and it's seems like you have a supportive father. The majority of doctors won't be judgemental and I don't don't think he/she would make you uncomfortable with certain questions.

worried that the doctor will think I'm odd because I might have it.
^^^^
Please don't worry about this because your doctor wants to help you, not judge you. I've said this before - I believe mental illness(especially when there's a chemical imbalance) is a physical illness, like any other physical illness and there shouldn't be a stigma attached to it. If you're concerned about the fact you SI or have used alcohol - this is up to you, if you want to reveal this to your Dad at this time. I think if you're comfortable, you may as well bring it out in the open soon. I bet your own dad drank when he was younger and you may be surprised what else he did LOL. I'm a parent and I would like to know those things, if I were in your dad's shoes.

This doctors appointment will involve you explaining how you feel and how long you've felt this way and whether there are any outside stresses involved. The doctor would then decide if you need medication or to speak with a psychologist or both. Your doctor won't be making you feel like you're on the witness stand. Remember feeling sad and needing help is nothing to be ashamed of. Did you know many substance abusers are actually self medicating themselves, instead of reaching out for help, as you are? Good for you and good luck. Please let us know how it goes.