Getting sick more often...

This is a pretty complex question. First off your training plans needs to add stress each week at a rate that your body can handle. This is called periodization and an example would be weeks of 10 hours, 12 hours, 8 hours. The 8 hour week would be the rest week.

More importantly imo is the amount of sleep that you get and how well you eat - I find that for most AGers if they could get more sleep, they would get sick less often and improve their fitness as well.

Hope this helps.

Hey Kris...

 There was a point when I was first running long distances that I would regularly get cold-like symptoms the day after a long run.  I always assumed my immune system was low after the hard effort (never verified this with a doctor or anything).  It just stopped happening after a while and now I very rarely get sick at all...

I never modified my training, just kept doing what I was doing and the symptoms stopped as (I assume) my body got used to the effort.

This is very important! Until I began really paying attention to what I eat and adding naps whenever possible, I was usually battling some sort of sickness and/or fatigue all the time.

I would agree it's not enough sleep and/or ramping-up in volume too much.  My 2 and 3 year old are starting school and all those other social activities-that means they are routinely (at least once a month) getting colds and flu's and bringing something into the house.  If I get my requisite amount of sleep and maintain my training volumes (not building much), I won't get sick - and I used to if I fail in sleep or overtrain!  I have avoided the last 3 plagues that befell my entire family. If anything, I just lose a little energy for a few days as my body 'tries' to get sick, but I'm quickly over it and never go full symptom.

Of course this means I'm going to be laid-out for a week the next time they get sick! 

Wow.  Not to belabour the point.. but you're doing a LOT of training for a beginner.  You're doing about twice the volume I do, and I've been training for 1.5 years (and have several races under my belt).

If you're not sure about what kind of training you should be doing, I would check out the many training plans available on this site.  They're formulated to increase your volume in each sport at a rate where you're unlikely to get injured or sick.  And yes.. sleep.  Sleep lots.  Play lots.  Make sure you have rest days at least once or twice a week.