GG
I have been where you are. It's horrid, I know.
I found that when my ds's became less dependent upon me for their every need, and I started to have a little time to myself, that I suddenly felt awful - really lethargic and unable to get back into any routine that I had to organise. Six years of broken nights and being at the beck and call of little people is exhausting. How many dcs do you have?
It sounds very much to me as if you had pnd and your mind/body is now making sure that you give it some tlc. I agree with Evesmama. If you have been battling on, then things will come out eventually. Your symptoms are classic of depression - I don't know whether untreated pnd leads onto depression, but I would bet that there is a link. Do try your GP. If necessary take along a copy of this post, so that you can describe as clearly there how you are feeling.
If you don't feel able to go to your GP yet, then there are other things that you can try:
allow yourself to feel like this for a while. You have worked hard bringing up your family and coping with ds's illness. It's OK to feel tired!
diet: try googling 'mood enhancing foods' (bananas are brilliant - others may be able to suggest more) and boost your body with some vitamin supplements, with iron in.
do aim to get out each day - a walk to the park, to the local shop or even just getting out into the garden. If the kids are out at preschool then you can try a brief 'power walk' alone mid morning/ afternoon going at your own pace, and not having to stop to look at every ladybird/ stick/ dandylion (preferably avoid walking first thing in the day, you may well droop onto the settee afterwards, feeling even more tired)
Don't feel guilty about the house. It will wait. And don't feel as if it is your job to sort the whole house out. On the other hand, just doing one thing can be really good. Choose one job to do, and see if you feel a bit better afterwards. Run the hoover around one room. Wash up. You may feel up to doing a second job.
Sleep. Treat yourself to some early nights in bed, with a good book (I find that an evening's telly really makes me feel worse afterwards, really lethargic). Change the sheets and enjoy being in bed alone. It can feel like a real luxury.
Get out. Organise yourself some nights out for you. Treat yourself. And if you can afford it, join a gym - the mixture of getting out, meeting others and getting exercise can be brilliant. And they may have an introductory offer, even if just for a month or two, to get you kick started.
Have a list of things which you really need to get done, and tick off anything that you get done. Add on all the extra things that you already do - getting the kids dressed, shopping, cooking. Don't feel guilt about the stuff that doesn't get done. But give yourself a pat on the back for keeping your kids fed, clothed and at school. That can be a day's work in itself.
Good luck