There WILL be good times and you just have to allow yourself to recognise them when they arrive. I'll take mediocre and boring days whenever I can get them - sometimes in their own context, they ARE the good times -like yeah I got through an entire day without some crap happening to me.
But yes there are times when I feel like you, that "there shall be no more" but then something happens and I smile or chuckle or straight out LOL and THAT moment is worth it.
You just have to hang on to hope even in the darkest hour just push through and hang on.
Also, I highly recommend having a pet as they can be the source of greatest amusement, unwavering admiration and loyalty and unconditional love.
Jack Russells Foxies and Pugs are particularly good at this

- they don't give a rats bum if you're not happy - they need feeding and walkies and playime and then they will make fools of themselves for you and cuddle.