I believe you are right. I first noticed my hair loss when I was 23, and just started a new job. I didn't like the job, I hated the commute, and I wasn't ready for it at all. I started drinking this really bad coffee they offered there, and I noticed then and there that coupled with the stress and depression, my hair started to shed. It continued to shed throughout the years, and I continued to drink coffee.
The strange thing was, I'd have these days where I'd brush my hair and just watch dozens of strands fall out at a time. Then, not many at all for a while. The last time this happened was just a few months ago, and while I quit coffee, I'd switched to Red Bull. Still bad news.
Now, I try not to drink any of that stuff. I had a red bull last week, a few days in a row because I needed to get some packing down for a move. But now, I've got to be committed to it, as my hair is only getting worse!