By the time I got to grad school I knew what I wanted to do, but it took me a while (5 years) in between undergrad and grad to figure that out. In college I had no idea, so I guess you could say it took me 10 years (5 of college and 5 of working before grad school) to figure it out.

In many ways, I wish I'd gone really with what I had a passion about, namely vegetable gardens and bicycling. I did get a masters in landscape architecture and another in city planning, but my thesi were not focused on these two passions. They could have been, easily, in my field, but I chose what I though were more acceptable and mainstream topics.

There's the old classic, What Color Is Your Parachute, that is really good. I also found the Myers-Briggs helpful in figuring out how I best work (not what to do, but how to work within my natural way).

I totally understand how you feel overwhelmed. Even now, I have to say no to projects and activities because otherwise I just drown in them! You CAN say no to activities. In fact, it's probably a good idea to say no because then you can do whatever you do better, as opposed to spreading yourself too thin and not doing anything well.

Don't forget to take care of yourself. You can't take care of business if you don't take care of yourself.