Amy-
These are the EXACT thoughts I had a couple years ago when starting classes in grad school. Well, I realized ALL I was doing was living for the future. I was going to school, which was making me sick cause I wasn't working out and eating and sleeping right. So, I decided I'd rather be around as long as I can and live for the NOW instead of making myself stressed and sick, so I dropped out. I've never been happier. My PFTs and weight are up some of the highest without IVs in years. I feel great. I travel a lot and spend LOTS of time with my famiy (which I also missed out on in my years of working and schooling).
Although, I do often think, "wow, I wish I could be "normal" and successful and do what I went to school for", I also realize my life is more fullfilled now and I am doing everything (well, almost) that I want to NOW, so I won't look back and regret it cause I was busy with school or work that I didn't spend time with family, travel, take care of myself, etc... That's just me. I do wish I could have both... work, school, family, health, etc., but I know for me that is not possible, so I prioritized and made peace with that. I've since gone off antidepressants (for the past 8 months I've been off all antidepressants and antianxiety meds. for the first time in 10 years!) I also no longer am so anxious that I'm bedridden and sick to my stomach. I am a more peaceful person.
Now, this is just what worked for me and how I feel. I'm not suggesting this is the path to happiness for everyone. Everyone needs to search their own soul and find what will make them happy NOW. That is really ALL that matters. If your work, school, etc. makes you truly happy right now, I say great. If you're doing it only as a means to an end (that may or may not happen), maybe that's great for you, but if you're not happy about that, maybe you should rethink your priorities. Many people stay in unhappy situations so they may retire rich, but if they died the first day of their retirement, would they look back and think they'd lived a fulfilled life, or would they think, "hm.... i wish i'd have done a job that I enjoyed (maybeb just worked at a coffee shop or something simple) even if it wouldnt' have made me tons of money." I think very few people can live in the now, but I also think most CFers have been given this special aspect of life that we CAN see our time is limited and CAN choose our NOW so we may live NOW and not "later". JMO.