Living worried about the future and reaching mindfulness

I'm going through a lot. It's very easy to be lost in thoughts and worries about the near future, and that leads me to a life of unhappiness. I also feel guilty when I fell happy, because I feel I should be worried. For me it's very hard to accept the idea that the universe is impermanent and hence I should live the present moment when I'm responsible for things to go wrong or right. How can I solve my problems if I'm not totally immersed in the future, thinking about all the possibilities? If I need to think about the future, there's no way to not be anxious.