The Jewish Sages teach that the definition of a “rich person” is someone who is “happy with what he has”. This may sound like a somewhat simplistic formula for happiness and satisfaction, but it is very difficult state to achieve. However, it is the key to a tranquil and contented life.
What are our Jewish Sages trying to convey to us? The message is that whatever we have right now is what God wants us to have. If we could only understand that and internalize its meaning we would not be forever looking over our shoulder at what the next person has. We would not be always gazing in the store windows eating our heart out because of a product there that we didn't even know we wanted until a moment ago.
There is a very famous quote from the late cartoonist Bill Keane that really sums up the way that we are supposed to approach our lives. "Yesterday's the past and tomorrow's the future. Today is a gift — which is why they call it the present."
Perhaps you can use that saying as your motif in your own personal battle against worry about the future.
I wish success much happiness and success in all your endeavors.