There is room for improvement, just to start a few:
I think it necessary to write something, and Looking back my 2016,
grammatically wrong, "it's necessary", "look back at"
Looking back my 2016. At first, I bore the failure of the university entrance exam and kept negative attitude to my college life. I was unwilling to contact with my new classmates. I didn’t take part in any activities as far as possible so that I make few friends. But I didn’t care and was happy to be alone. On the other hand, my learning was bad. I always preferred play with smart phone to attend class. Unexpectedly, I failed in the final examinations. Maybe failure stimulated me effectively again. I began to struggle. The processing was gradual and I didn’t know how to describe.
The text lacks a structure, I would prefer something like this: The past 2016 is really bad for me. After my failure in the college entrance examination, I kept a negative attitude to college life. Not willing to contact with new classmates, and take part in college activities, I left my self to be alone. On the other hand, my study was also bad. I spent a lot time on smart phone while attending classes, which resulted a severe consequence -- I failed in the examinations. Maybe failure stimulated me effectively again. I endured a long struggle, which was hard to describe.
The main problem of your original text is the lack of structure or logic linking.
I'll leave the rest parts to yourself to improve.