I am almost sure that I have inattentive ADD

Just bear with me for a few minutes. I just finished my first semester in college and now I am almost sure that I have ADD. Let me tell you why and tell me if my self diagnosis is correct.
- I cannot focus in lectures. I keep trying but in 5-10 minutes, I just zone out.
- I am terrible with directions. Even if I have been somewhere 10 times. I never remember how to get there regardless of how I am traveling ( in car, train or bus.)
-I make really careless mistakes. I know how to do math problems but I get them wrong because I for got to move a number, put in the negative, etc.
-Constantly forgetting appointments, social engagements, etc
- I can never get assignments done unless I do it the night before it is due
-Hard time following instructions or directions
-No organizational skills
What do you think?

Can't say yet, from what you've wrote.

What is your motivation like?
How is your memory (besides directions and scheduled events)?
What's your relationship with caffeine? cigarettes? drugs&alcohol?
What are your energy levels like?
Besides lectures, how are your listening skills?
Do you get bored often and quickly?
Do you create long-term plans and stick with them?
Do you get easily frustrated?
How is your follow through with anything (tasks/projects/hobbies etc)?