Oh I know it's not deliberate, of course it isn't! You're trying to hold everything together so you're probably busy let alone stressed out!
I'm guessing you're in the UK with that kind of waiting list, I reckon you need some time to be selfish so you have time and energy for your family. If you're in the UK, it's worth contacting Homestart:
http://www.home-start.org.uk/homepage or if you're not in the UK or not in a Homestart area, try using your local health care professional for support (HV, GP, doctor). Ask family too. Is there someone you could ask who could look after your son for a couple of hours a week to have a bath, chill out etc? I also really recommend getting out. I find the day goes more quickly if I'm having a bad day if I get out; go to singing or reading groups (try your local library or surestart centre if in the UK), go swimming, go out to the park, go to a local farm... All the fresh air will help you both and help his appetite.
I hope you get to see someone sooner. It's not as good as seeing someone face to face but here's a link to an online CBT course.
http://moodgym.anu.edu.au/welcome it might help tide you over.
Good luck. I hope things improve soon.