Last year, I had three episodes where I was speaking and suddenly, I couldn't understand the words I was saying, but they could understand me.?

A type of aphasia... A type of aphasia...Or speech/language difficulty were you may have difficulties speaking or understanding language, sounds a lot like your symptoms. Regardless of any other medical problems you have, you should discuss this with a doctor, who may send you for a neurological examination. I wouldn't ignore the symptom.
Check with doctor. Symptoms like you are describing are similar to those seen in stroke patients. All lot depends on your age and other risk factors. Do you have high blood pressure. Is there a history of strokes, heart disease in your family.