I hear ya. I don't think I have a good life. I've had a comfortable life, for sure, economically speaking, though no longer. I'm old (at least in my perspective), too late to try and pursue any dreams I might have had since the careers I most enjoy are artistic and women in their 30's are considered past their prime. I don't have a job, I don't have any money or savings, I don't have a boyfriend, I don't have kids. All I have are my pets. So yeah, my life isn't a fairytale, but it's also true I'm not terminally ill, I don't have chronic physical pain, and though they've been nothing but cruel and un-supportive, I do have a family.
I'm often told I have "a privileged brain", since I'm believed to be very intelligent, but I don't feel like I am. I feel rather stupid when it comes to forging meaningful relationships with people, or even with myself. I lack the know-how of daily life and the drive it takes to get up every day to do the same thing, for the same amount of money, for 20+ years until you can retire. I just can't cope with all that. So I don't feel very smart, and I feel guilty for wasting my life and my supposed intelligence in wallowing in self-pity and guilt, but it's also my built. It's like I'm just programmed to be this way, no matter how many times I've tried to change.
Circumstances for each of us will defer always, if only ever so slightly, because every person's head is completely different, every person's childhood and upbringing and life events and circumstances are different, so we can't generalize what drives a person to feeling so down in life. Good post! I like philosophizing like this.