Insomnia like this is often a symptom of depression, and the irritability and sadness certainly is as well. Certain sedating antidepressants like trazadone or low dose amitryptilene can help a great deal. It’s also important to entertain the possibility of sleep apnea causing the daytime symptoms. I would discuss this with your Dr. Many PCPs will prescribe those meds. They are safer than sleeping pills and not addictive so can be used long term. They are both very old, tried and true meds, and are inexpensive. I hope you will consider this and talk to your Dr. A good night sleep is essential!