Firstly, there's a difference between dealing with being alone and dealing with the emptiness of losing someone you love.

For being alone - many people will suggest you should try to get out and socialise, but imo this isn't a good coping strategy. I'd argue you need to learn how to enjoy your own company rather than be dependant on others for happiness. That's not to say you shouldn't try to get out the house and socialise from time to time, but it also shouldn't be painful for you to spend a few days by yourself.

Meditation will help with this. I used to hate being alone and would constantly try to fill my free time with social things to not feel alone, but I really enjoy being in my own company these days and never feel lonely anymore, even if there are times I want to be social. That took a lot of introspection, but I'm much better for doing it now.

Dealing with the emptiness of losing someone close is the harder bit here... I'd argue that again, you should try to embrace the pain rather than find ways to avoid or silence it.

First understand that one can replace the person you loved. Even if you find someone new, they're not the same person and will not replace your loss. This is why going on dates and trying to find someone new cannot work and if anything will only make you feel more empty and lost in most cases. You need to find ways to come to terms with your loss while not letting it control your life or overwhelm you.

I've been depressed for the vast majority of my life and I want to die almost every day, but for me it's quite manageable because I've learnt how to allow that pain be there without controlling me (more or less anyway – somedays can be hard). In my opinion medication, drugs/alcohol and other methods of silencing the pain don't work well long-term. You simply have to learn how to manage your mind.

My advice would be to go for a walk with your dog, not to avoid the emptiness you're feeling, but to embrace it. Go out specifically to experience how much it hurts going for a walk without the person you love by your side. Be really inquisitive about all of the emotions and thoughts that appear in your mind, and slowly learn how to come to terms with them.

Please don't take this as me suggesting you should come off the meds, but I do worry about you being on a cocktail of drugs to manage a natural human emotional response to loss. Keep in mind meds can also make you feel empty and unmotivated, but more importantly they're not much better than substance abuse as a means of coping with pain in my experience – prescription meds are just the socially acceptable way to do it. People will say, "yeah, but they work", and that's true of course, but it's also the problem. I can say from experience that alcohol extremely well as a way to manage emotions... But ultimately these are not good long-term strategies for dealing with emotional pain - assuming you rather not be dependant on these substances. But maybe you don't care about that, and that's fine. I have my reasons for feeling the way I do so can only speak from my own perspectives as someone who has struggled with the emotions you're feeling and nearly allowed it to kill me as a result.

Best of luck. At least being human is interesting, huh?