Don't be so hard on yourself harlequin. And don't just bin this design. You've just received some great feedback, so why not put it into practise. Work on the poster, improve it and come back for more critique. That's the best way to learn. Criticism is part of the life of a designer but you have to turn it into a positive. Each time you take feedback and learn from it you become a better designer.
A work placement would be really benficial to you but in the meantime make the most of the forum. It's the equivalent of a placement as it's full of experienced, professional designers who aim to help you improve.