Is it possible that my hat has gotten rather thin due to prolonged emotional stress? and what can i do to alleviate the loss and encourage hair growth? im 40 yrs old.

Many things possible: One's primary care doctor can check for medical causes. If none are found, then one can see a dermatologist, especially one specializing in hair restoration (some treatments: minoxidil, etc,...). Medical causes may include: hormonal problems (low thyroid), seborrhea, alopecia areata, stressful illness. Other causes: genetic male/female pattern baldness, telogen effluvium.