It's sad but, it's not a worst part of your life. Stop being demotivated and try to find alternatives. It's not necessary to get into engineering college to be successful. So try to find other good career choices like doing various types of Diploma or B Sc. If you are sure about taking engineering then either consider taking a drop and study PCM again. It would be diffficult to perfoem well in enginnering college without PCM knowledge.