On a plateau,,,, Help!

Find a race....soon
or
Do a neighborhood 5k or something. Pick apart your performance and you'll have something specific to work on.
or
Have someone look at your swim stroke and give you some ideas on how to improve
or
Get a standard ride and time yourself on it. Go really hard. In two weeks, do it again, see the improvement.

or all of the above

Supplements (a good one!) make all the difference in the world, in addition to sleeping well, etc...

I started using about 2 weeks ago "Life Basics," which is a multi-vitamin in liquid form. I've been using liquid vitamins for the past 6 months now, and I would never go back to pill form. It absorbs into your bloodstream quicker, and is just a better quality than your Centrums, etc...(no offense to anyone who takes these) This is by far the best supp I've ever taken--I feel very energized all day, and don't get sick along with everyone else at work. Knock wood.

If you can't find a liquid kind, then go for a powder form, which you can mix into fruit smoothie. "Super Food" by Dr Schultz is great, but I just don't like having to dirty a blender to get my vitamins for the day. Lazy, but true. In any event, make sure that the compound is from a whole food base, and uses "phytonutrients" which come from sea vegetation.

I wish I could give you a website addy, but the website off the bottle isn't working for some reason. I'd check around with your local health food stores...GNC most likely won't carry this, because it's not one of "theirs."

Also--are you getting enough sleep do you think??

I have read that mild depression (losing steam / drive i.e interest) is a result of overtraining. And overtraining is individual to each person, so don't let anyone judge it from your logs if you make them available.
When is your first event? Do you have time to take a week off from training and do other types of physical activity (hiking, rowing, whatever?).
Do you have any training partners? Sometimes that is helpful, the accountability factor gets you over those first few tough moments needed to get you out the door. Even a 'virtual' training partner might help!
I good quality multivitamin is sufficient 'supplementation' - everything else should come from diet. Are you watching your diet and hydration?
Just some thoughts. This happens to me quite a bit, combination of overtraining and dealing with some incredibly stressful life things that would keep most mere mortals in bed with the covers over their heads, whimpering.