Buy a mobile at the Carphone Warehouse through this link and Mansized can make up to £45! Every order you place helps us build more great stuff for you
Firstly, how important is it that you finish your college course, what ramifications would it have if you quit (either quit and stay at work, or quit both course and job at same time)? Presumably you cannot quit job and stay on course.
Can you speak to someone in HR as well, get them on your side?
Ultimately though, it comes down to your immediate manager and the CEO. I think you need to write down everything that is wrong at the moment in a series of coherent points, then demand a meeting with both of them present. I know sometimes you have problems being forceful and demanding attention, but you need to do this!
Get them to sit down with you for an hour or whatever, and calmly go through the points and issues. Emphasise that you are seriously not happy, that you are not getting enough support for the multiple jobs you are doing.
Worse comes to the worst, you can always leave. That option is always there, it just depends if things are so awful you need to resort to it. But if they are not treating you well, then you owe them NO loyalty and you need to look out for yourself. 5 years of work surely demands that they do something for you.
If you want to treat yourself to some chips I'll look the other way ;)
I haven't got that much more to add to all the excellent advice given above. But I would echo Phoenix's comments about talking with HR. If your HR officers are good they will help steer you through the best way to talk with your line manager so that he can understand how you are feeling and your concerns for the future.
If you decide to talk on a 121 basis with your boss when he's back (which is always a good first step) make sure that make notes of evrything that both you and he have said - it can be really useful as a memory jog and also if you need a more formal reminder.