Health worries

Many years ago I recovered from a serious illness that took many years of suffering before discovered, this was hard both physically and psychologically. I have come a long way since than and are now having a healthy good life. However now and then (may triggered by the corona situation) I get a “hang up” of negative thoughts if I experience some normal minor health issues. An example now is that Im having a urinary infection that is mild but the doctors are not sure if its something else so they don’t give me antibiotics and say since Its mild it will most probably go away in a couple of weeks. My thoughts are: this can be the start of something bad and then keep spinning.
Can you help me with creating a better model ?