At the top of the list is making human contact. Never worry alone. Toxic worry usually attacks the solitary mind. Next, get the facts. Toxic worry is a disease of the imagination, usually rooted in misinformation or lack of information.
Exercise is a great antidote for worry.
I go into over fifty remedies for worry. Most do not require seeing a professional, but when indicated professional help is highly effective these days. As I said, toxic worry is as dangerous as high blood pressure. I think that is very exciting. For people with ADD, worry is a kind of self-medication.