Pretty much described this anon, especially 3 & (4).
>my three children
Focus on these, anon. Teach them. Share with them. Listen to music (preferrably old music, hit up some Mozart and/or Glenn Miller, even!), play physical sports with them. Have a catch!
Try to detox them from screens, especially TV, fakebook & such – most important that they do so. Make them not even miss it.
Many people can't have children for various reasons. You have three.
Personally (thankfully), via Divine Interventions and unexplainable "coincidences", God stepped in. Stories too far-out to share but don't count God out. At least look and try to notice these things. May think you're going nuts, but you're not. Was just a teen and talking like you are now. Walked into an empty church (was jaded by the "Catholic organized Corporate religion experience, so went that day for own reasons); Reached Up. Saved life.
Throughout most depressing days (of which there are many), looking back at the unexplainable "coincidences" has been the Main comfort.
Give this a listen. Music does help. He would become Captain Glenn Miller (WW2) …