How does one deal with no motivation and going through the motions of life?

I'm sorry to hear that you are going through so much pain right now. It definitely sounds like you are struggling with depression as you are listing symptoms of depression. It can be really hard to shake depression, but it is possible.

It would certainly be worthwhile for you to talk to you a therapist to better help you address these symptoms. The therapist may use approaches such as Cognitive Behavior Therapy (CBT). CBT can help you identify and change negative thoughts that are reinforcing depressive symptoms. It also focuses on changing behaviors to reduce problematic symptoms. CBT has been proven through research to help address depression. In addition, you may want to look into scheduling an appointment with a psychiatrist because an anti-depressant may help reduce the symptoms.

Something else that you can do to help reduce the symptoms of depression is to exercise. It may be really difficult to motivate yourself to exercise, because depression does that. However, if you can exercise for even 5 to 10 minutes a day to start out with, that can be the best thing to help reduce depressive symptoms. It is almost like you have to fight the lack of motivation by moving your body. Exericse actually has been proven through research to increase chemicals such as serotonin in your brain. People with depression tend to have decreased serotonin levels, and increasing this chemical can help reduce depression. Start with going on a 5 to 10 minute walk in your neighborhood or nearby area. Try to set a goal for once or twice a week to exercise. Then you can gradually increase how much you exercise if you want to. 

I would also recommend trying to engage in the activities that you used to like to do. For example, if you used to like to draw, then try drawing something to engage yourself again. Maybe you used to like to go to dinner with friends. Try inviting friends to dinner. Engaging in social activities can also help reduce depression as it reduces isolation time.

You can also try practicing some relaxation skills such as diaphragmatic breathing or progressive muscle relaxation. You can look up videos online that will teach you how to use these relaxation skills. It can certainly help with reducing depression. You can also utilize skills such as visualization or mindfulness meditation. You can find videos online that will explain these skills as well.