I can understand the distress you are through. These could be symptoms of depression or stress problem. Stress is a major cause for depression. In some cases, there may not be any specific cause seen. It can occur to anyone without any reason. Most importantly, it is completely treatable. It is important to know that it may not get resolved on its own, it must be managed like a medical disorder which may require medications as well.
Next Steps
I would strongly suggest that you must consult with a psychiatrist. For detailed information you can directly consult here on practo.
Health Tips
Don't worry. There is a solution available. You can be normal again.