It's not just teenagers who are apathetic. The economy at the moment is such that even the best of us can be swamped by apathy occasionally. So, if you're affected, the question is how to overcome apathy
Chances are that you're not apathetic all the time. Some things will excite you such that you'd drop near enough everything else to do them. Notice how you feel at those times - the tingle of excitement, that kind of thing. Then switch that feeling into another activity where you've recently experienced apathy. Transfer the feelings. Pretend if necessary - our minds can't tell the difference between something we imagine vividly and something that's truly real.
It could be that the reason you're not feeling particularly enthusiastic about something is that you truly don't care about it. Sometimes you can't avoid this - doing your tax return only seems to excite people like accountants or the IRS - but a lot of the time it's something you've chosen to do that no longer hits the right buttons in your mind. If that's the case, take the time to check whether your goal is still in line with your current aims. If it isn't, switch it for something that does. We change over time so there's no shame in changing what we want to do or aim for.
Work out a system of rewards for yourself when you complete a task that you would normally associate with an apathetic feeling. Maybe a treat such as a cookie will work. Or maybe the amount of apathy you need to overcome is bigger and the task is bigger so you need to award yourself a bigger treat. You'll almost certainly know what excites you and be able to tweak these mini rewards accordingly.
Wallow in your apathy
This sounds contrary but it can work. If you wallow in your apathy and get enthusiastic about being apathetic this can really turn your mood around. Weird but definitely worth a try!
Get some exercise
Exercise releases endorphins - the naturally produced "feel good" hormones that your body creates, especially when you've done some exercise. The good news is that you don't have to work out for hours in the gym. Any form of exercise - even walking up the stairs - will do this and release endorphins into your body.
Set some easy goals for yourself
An easy, quickly achievable goal could be all that you need to overcome your apathy. The thrill of actually hitting a goal rather than constantly missing it will have a knock-on effect. Once you've proved to yourself that you're capable of hitting a goal - even one that isn't exactly big - then you can set your next goal slightly bigger and so on.
Check your posture
Slouching and staring at the ground all the time will naturally lead you towards apathetic feelings. Sit or stand up straight. Lift your head up. Maybe even allow a smile to creep onto your face every now and then.