Racing thoughts, wasting lot to time thinking and worrying, not able to relax, low mood, problem with getting good sleep, bodily complaints of headache, tiredness, etc are few important symptoms of anxiety disorder. In your case a general anxiety disorder appears likely. There may not be a specific cause to this, but the cause can be multifactorial. Stress being an important risk factor. Depression is the most common secondary complications. In chronic cases, it may predisposes for hypertension, diabetes and other stress related problems.