How about talking to someone about changing your subjects and your difficulties, surely they will listen and be reasonable about it, as long as you're up-front, honest and willing to do something about it to help yourself and have the right attitude. If you have same attitude you have at the moment of just giving up because it's too hard, you're not going to get anywhere with the ATPL and may as well just forget about it. Harsh words, but you need to hear the truth of what is required of you in this industry. ATPL theory is not a walk in the park (unless you're a genius like me, which you aren't) - so if you can't handle this, you've got tough times ahead.
Do something about it and work with your teachers rather than giving up.