Do yourself a favor and steer clear of heroin. Heroin is man made crap. Allow me to let you in on a little secret. Mother Nature already anticipated that there would be people like you that can't handle their lives sober and need some drugs to cope. Guess what. She created a plethora of them, the majority of which will do you much better than heroin. Have you tried any of the following: Kratom, opium, cannabis, kava, psilocybin mushroom, coca leaf, San Pedro cactus, Amanita Muscaria to name a few?
Note: I am not saying all synthetics are bad, I am just saying in general when you take a plant (like the opium poppy in this case) and then take out the most potent active chemical and make it super pure, you end up with a far more dangerous and less balanced substance than you originally had with the plant. I used to have access to loads of heroin as well as a similar thing happened to me as somnilicious. You get to a point where there is no where to go. All you care about is your next shot and the rest of your life consists of laying around, sleeping off the sedation. You lose the motivation to experience life because normal feelings become painful in comparison to opiated numbness and as soon as opiate levels in your bloodstream fall past a certain point you are too sick to enjoy anything.
I'm sorry but this is total crap. How exactly is opium less dangerous than say, morphine addiction, and how is morphine addiction less dangerous than heroin addiction. The only argument that might hold any validity at all is that with the plant matter you can't end up using the needle. But this whole Mother Nature thing is bullshit. I wouldn't care, but it's dangerous advice.
Being man made doesn't equal bad, antibiotics are man made and have saved countless lives.
And being natural CERTAINLY doesn't equal good. Ricin, smallpox, anthrax, Botox, cyanide, these are all natural things too. And they certainly aren't good.
Pharmacologically, which is to say, in the way that actually matters, heroin IS safe. It's not a toxic drug and it is as safe as drugs can be. To say otherwise is to use such a broad definition as to render the word "deadly" or "toxic" meaningless.
That said, heroin most certainly IS bad, and heroin addiction can, and does, kill people. The drug may not be inherently deadly, but neither is water, but too much water can kill you by disrupting your electrolyte levels. Many otherwise nonlethal things can kill you if misused, but the nature of heroin leads itself to being misused far more than most. So it may not be harmful inherently in the chemical sense, but it most certainly leads to great harm in a less direct way.
Personally what I think this shows is that simply categorizing things as lethal or dangerous or safe. Toxic or not toxic. Is so simplistic as to be wildly misleading. Much better to actually learn the full story so you can get the whole picture, and forget about all the simplistic labels.