I am worried about my present. I do not know my previous birth and have no chance to know my next birth. Humans would have known of their past and future if The Almighty wanted to give this capacity to the human beings. But we know that He by His supreme Will decided not to bestow the Humans this sense.

My Guru tells me that Waheguru Ji has given me this human form and this is a chance for me to meet my Creator.
Guru tells me not to miss this chance. My Guru has tried His level best giving so many examples and in a language that I 'may' understand telling me to make use of this human form to meet my Creator.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/sikh-sikhi-sikhism/26474-support-for-the-concept-reincarnation-sikhism.html

He tells me this is the only chance. My Guru tells me to lift myself spiritually to attain the the strength to merge with that being who created me.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=26474

The Creator has given this ability to the Humans. But we need to follow our Guru.

I am not worried about Reincarnation.