After all of my recent bike frustrations, I am happy to report that I finally had a good ride on Saturday. I took all of your comments to heart and went out with a goal of staying relaxed, not worrying about time and finishing on a positive note. The only thing I did not manage to do was ride with a more experienced cyclist, but I'm just saving that one for another time (and accepting volunteers). :)
I think the ride was successful for a couple of reasons:
1) I went on Saturday and I went early - I have been doing my long run on Saturdays and trying to ride on Sundays but I knew that it would be better for me to get the ride "out of the way." I hadn't been on my bike since Monday and I knew I needed to get back out there and silence the nerves. I also planned to get out as early as possible so the trail would be less crowded. This also turned out to be a good idea given the crazy heat that has been hanging around. I ended up starting at 6:30.
2) I drove and rode where I knew it would be less crowded - For some reason I had been feeling like I really should be starting all of my rides from my apartment since I can be on a number of the local trails in minutes. It seemed silly to drive somewhere with my bike to ride. I decided on Friday that I should try to ride somewhere that would be less crowded (i.e. stressful) and that there was no shame in driving to a location where I could have a better ride. I ended up looking up parking locations for accessing the W&OD trail and then driving out to Vienna and parking at the community center. This was a great decision. I rode west and the trail was significantly less crowded than it is around Arlington. I had to pass groups of runners, but I never was worried about it because there wasn't a steady stream of runners/cyclists/walkers coming the other way.
3) I loosened the tension on my right pedal - This is the foot that I put down when stopping and it really calmed my nerves to know that I could get it out of the pedal with minimal effort. I didn't really think that it was all that tight before, but it did require a more concentrated effort to release my foot. Now it comes out easily and quickly. I'm sure that this means I am sacrificing some power, but the loss there is totally worth the mental boost. And it's not so loose that my foot comes out when I'm pulling up. As an added bonus, I can get that foot clipped back in much more quickly when I start up again after a stop.
4) I had the right attitude - I really focused on being positive and staying calm and in the moment, rather than anticipating problems that might lie ahead.
It was definitely great for my confidence. I'm sure there are still plenty of ups and downs ahead, but I just need to remember to focus on the right things and not anticipate the stressful ones and I'll have more good rides than bad ones.