Your question touches on several points, so I will answer them one by one.
a) What happens before dying?
This depends on the manner in which death occurs. Some deaths are gruesome and entail unimaginable physical pain as well as psychological anguish. Others are peaceful, not any different than falling asleep.
b) What happens after death?
I believe that you die when there is no more brain activity, i.e. when those parts of the brain which regulate the central nervous system stop functioning. Your heart might still be beating, you may still be breathing, but you would be dead nonetheless.
Without a functioning brain, there is no consciouness, and without consciousness you have no perception of anything, including death.
So, my answer to your question is: nothing happens.
c) Should I be afraid of reincarnation?
Reincarnation is a belief. Beliefs are not factual knowledge, they are a matter of personal choice. Some people believe in life after death, some in eternal return, some in nothingness, some in alien beings who wait for us on the far side of the Moon. You are entitled to believe in reincarnation, but as far as we know, there is no such thing.