Overtrained?

I can tell a major difference between the way I ran last year and the way I am running this year at the same mileage marks - and it really isn't a good difference. My long runs are feeling okay, instead of great, and my short runs are feeling long. Also? I am constantly feeling like I am dragging, and between Friday night and Monday morning, I sleep about 30 hours. That's all I do all weekend. I come home from my long run, nap all day, piddle around the house, eat, and go to bed. Get up Sunday, work out, nap, church, eat, piddle, sleep. This can't be that good for me.

So I started examining the reasons behind why I am so tired and my runs are dragging. The difference between this year and last year is that now, I am actually cross-training. I do boot camp twice a week, yoga once, and I try to swim and bike at least once each per week - on top of two training runs and a long run. Boot camp lasts only one more week, fortunately, but at the same time, I almost feel like if I am not working out so much then I am not going to burn as many calories and get to eat what I want, and I'm not going to improve my cardiovascular endurance and my muscular endurance. Am I give out because I'm not in good enough shape, or am I give out because I'm trying too hard to get into good shape?

Then there is also this interesting "exercise-induced inertia" - if I keep moving working out, I'll keep moving in other areas. For example, last Saturday night, I could not sit still. If I sit on the couch, I'll fall asleep. I had to get up every five minutes to clean something. The upside is my house is spotless, but the downside is here I am scrubbing the cooktop at 11 pm when I should probably give it up and get in bed.

Somehow I need to find a balance. I'm hoping that boot camp ending will help a little, but I need to get it into my head that I am a runner, and I run. I can do a little bit of other things to cross-train, but not to the point of derailing my running. I know in the back of my mind there's a triathlon spirit, pushing me through breathless swims and grueling bike workouts so that when my triathlon comes - and I hope it will - I'll be ready. But right now isn't the time to stress the biking and swimming, because it's not important to my running, which is the main focus here. It's 144 days until the Vegas Marathon, and if I'm tired at 8 miles, then I'm going to fall over before I see the finish line. We can't have that.

So how much is too much and how much is not enough? Where do I draw the line between cross-training and overtraining?