I have some experience of this, having a cycling son who, aged 16, did the Tour of Normandy, which was 500km in 2.5 days.
Basically - if that's your training load, you're probably *overtraining* and setting yourself up for illness and injury. Ask any qualified coach (which, alas, I'm not, I'm just the mum of a young cyclist who does get coaching) and he or she will tell you that rest & recovery is a *vital* part of any training regime. I know of young athletes who have upped their training regime a lot and they have indeed come down with various nasties. Take care of yourself: healthy eating (lots of fruit, veg, carbs and protein), keep hydrated, yes, plenty of exercise but also LOTS OF REST. Recovery time is where your body builds on the works you've put it through.
As an example of training, my son's weekly training plans *always* included one day a week off the exercise.
If you are otherwise healthy, I'd be suggesting taking a few days to a week off the exercise. Rest, recuperate. Eat wisely. During that time think about drawing up a sensible training plan that includes a rest day each week.
Fitting in cycling: do you cycle to and from school? That's the main way my son built in some base miles.
I'd also suggest:-
Get yourself to your doc for a general check-up. You're probably fine, but it's worthwhile getting checked to make sure you've nothing nasty brewing.
Think about getting yourself a proper coach. If you want a general fitness coach - is this something your PE teacher at achool can assist with? If he or she can't personally, perhaps they can suggest someone. If you want a cycling specific coach, the British Cycling web site gives details.
When you are exercising, make sure you are hydrated *before* you start exercising, during exercise and afterwards. Isotonic drinks are good stuff. Post exercise think about recovery food/drink with protein in it. If you exercise over any length of time, make sure you are eating/drinking little and often to keep your blood sugar levels up. In cycling there is a term "the bonk" and no, it's not anything to do with that girl in the GCSE French set, it's to do with running out of energy quickly. Eating & drinking little & often during exercise will stop this happening.
Best of luck.