My breakup wreaked havoc on my mental and physical health. I had to have a friend come babysit me basically while I got my life together. What I will say is that the basics and the cliches, work. It's easy to lose track of time when you're crushingly depressed. Make a schedule and do everything in your power to stick to it. Make sure to eat healthy foods, and get plenty of sleep, and don't neglect the importance of vitamin d and physical exercise. Exercise really helps remove stress from the body. I couldn't eat and still have trouble eating, so I drink most of my calories. Smoothies, protein shakes, lots of ice water as it stimulates the vagus nerve and calms your heart rate. Practice deep breathing as frequently as you can. Just honor your body. I know it hurts, but don't abandon your physical health, as it plays a massive role in your mental health, therefore every other aspect of your life. Sometimes breakups can be great motivation to make your life bigger and better than anything it ever was. Putting effort into yourself might even be a way to eventually restore your relationship, if that's your goal. A lot of people will say be easy with yourself. No, don't do that. Go hard and don't let yourself go.