Do you think about your problems a lot? Of course you do, and by doing so you are changing them and probably making them worse.
Every time we access a memory, we change it. In numerous studies it has been found that the act of recalling a memory has the effect of distorting it in some way.
Over time, with sustained attention, the problems, pains and fears we suffer do tend to get worse.
Be aware of your thoughts, be aware of the feelings that your thoughts generate - are they positive or negative.
If your thoughts feel heavy, put them down for a while: