The void feeling is Depression. Youtube distracts from it, but reliance on distractors is only a symptom.
There are many kinds of depression, distinguished first and foremost by what treatment works on each.
That is the reason that "gold standard" double-blind trials fail to find that anti-depressants work. Imagine if you couldn't distinguish a broken arm from a broken leg, a broken humerus from a broken ankle. Trials of a cast on the left lower leg help only a few people, on the right only a few; left upper arm, right forearm, yada yada. "Casts are ineffective!"
Take the wrong meds, nothing happens. Take the right one, miracle!
There is no shame in medicating a problem: "If you can't make enough of your own serotonin, store-bought is fine."
It is entirely possible that losing 50 pounds, or exercising devotedly, or dropping carbohydrates and alcohol from your diet would also fix it. Medicate first, and then see if those help. There is no end of benefits to these other measures, but you need to get your brain working right first, or you set yourself up to fail.
In my case I was fixed up only two days after getting a sufficient dose of the right thing. A smaller dose had no effect, and other meds had no effect. Some kinds take weeks to build up before anything happens. I had five serious side effects (dry mouth, jaw clenching, ears ringing, dizzy spells, one more I don't recall) that passed after a few months.
You can get past this, with help. Get help!