Hi there M. -
This just made my heart ache as I read it, its such a tough thing to go through, isn't it? I'm going to comment on two different things, and although I hope this will help, please feel free to ignore the advice if it doesn't seem to work for you! FYI I'm a communications lecturer, and did a BA and masters in psychology, just so you know where my perspective is coming from!
1) In terms of the crying:
I used to find that my baby had almost an attention 'bank' and when it was really full then, and only then, would he actually accept some time on his own playing and occupying himself. How did I fill up this 'bank'? We'd play together, walk around together (in my arms or in a sling), and he'd have plenty of bodily contact with me and/or my husband (you know what they say about skin to skin contact as a newborn - we didn't necessarily go crazy with that, but I think there's something to 'heart to heart' time, when your baby is snuggled in close to you and can hear your heart beating again, like he did while he was in the womb - its incredibly comforting for them as long as you are fairly calm too).
Conversely, I found that if I'd gone through a few days of being a bit stressed out, distracted, very busy and not playing with him enough (getting ready for a party in the house etc., etc.) he'd be a lot more clingy and a lot less happy to spend any time on his own, i.e. crying more. I personally think that this is something that continues with them for life, and just simply the amount of time (with you) that it takes to fill up their attention bank, just diminishes over time...
Seeing things that way, rather than resenting him and his need for attention from me, really helped me to empathize a bit more with my son (which also really helps with the crying!), and understand what all the crying was about, and what I could do to fix it.
If that approach doesn't do anything at all, and you think giving him more attention BEFORE you start to try and do anything in the house rather than after he cries, isn't making any difference, it might be worth taking him to the doctor and trying to see if there are any other causes - such as food allergies (I'm guessing you've started weaning him already?) etc.
2) In terms of your mood, and feeling like you have no joy in your life - my heart goes out to you!!
I'm wondering if there's anything you can do about this while you are looking at ways of dealing with your son's crying. Are you sleeping ok at night? Does your son give you some good stretches of sleep at night/in the day and are you able to sleep when he sleeps? I remember so well the desperate days when I was extremely exhausted (and it turns out going extremely hypo-thyroid!) and just felt so low and moody it wasn't true...
I think different people end up in a low place for different reasons, and I think the term 'postnatal depression' doesn't really do this complicated time any justice at all. However, silly labels aside, if you are consistently feeling hopeless, having less interest in your future, taking less joy in the things you used to love, generally having a bit of a rocky road adjusting to the different challenges of motherhood (let's face it, those who don't have some tricky adjustment time are rare compared with those who do, so there's no shame in it!) and think you could be a bit down for whatever reason - please do feel as though you can get some help and support for it.
I know for me, it almost felt like I had failed admitting I was depressed, but it was a relief at the same time. Unfortunately the medical profession then also failed me for a while because they were so one dimensional and figured my low mood was down to sleep deprivation (my son had pretty bad colic and was a terrible sleeper) and chose not to treat me with any pharmacology/counseling rather gave me advice about getting the baby to sleep more. Looking back, I can see it would have been confusing for the doctors, but missing the fact that I also had a debilitating physical condition (severe hypothyroidism), one effect of which is depression, made me really angry, and made me wish I had sought help sooner/had better doctors.
I have no idea if any of this will resonate with you or not, but the advice of the other ladies here is really sound as well, and all are things you can try to alleviate the pressure you are putting on yourself and perhaps help to lift your mood a bit. What's the worst that will happen if the things you want to do, just don't get done?
Best of luck and feel free to email me if you have any further questions or worries. Please know that we're here for you!
Ax