I understand how you will feel, when everyone else goes to uni and your not. As Im kinda on my 2nd gap year, and I have an offer. I think the best thing to do, is to take time out, have a break and rekindle your passion for medicine- whilst also making money, to support your uni degree.
You went ahead and applied for med, to make a decision to study for over 5 years. Its not something you can decide quickly and because of that, I dont think you should be hasty and decide against it. As the reason why you want to study medicine, is still there, and it will not go away by studing Chemical engineering. You might find, you hate it and do poorly in it.
Im sorry for your bad news.