Don't see it as a big thing. Just do small things to start, you need less motivation that way. I was taught to always leave a room better than you found it. I find this really helps. So if you use it, put it away, spot something on the floor pick it up. If there are 20 toys on the floor, just do this each time you go into the room until they are gone. It will all help.
When you feel more motivated, tackle only one place at a time. It can be a whole room or an area of a room. Each time may help to motivate you for the next.
The area that most quickly gets out of hand is the kitchen sink area. So wash up after yourself, even one cup or plate, to avoid that sinking feeling when you see piled up dishes.
In terms of cleaning, I find that cleaning the counters and taps in the kitchen and the bathroom fittings are a great start. They glisten and the rooms smell nice, so it is a better reward than tasks such as vacuuming.
On days that you do not feel like getting out the vacuum cleaner, perhaps just use a dustpan and brush or sweeping brush. A small area cleaned is better than none at all. Sometimes, it is nice to avoid the noisy drone of the vacuum for rythmic sweeping in your own time (or to music) plus you get to see the results by putting what you sweep in the bin rather than it going into the vacuum.
Laundry can be a big headache. Don't automaticlly put washing into the washing bin, put it straight into the washing machine and when it is full start the wash. Do this every time you empty the washing machine and you will never have a mountain of washing.
The most important thing is that you cannot do everything. Prioritise. Any progress is progress. Reward yourself for your efforts when you can manage to make them and forgive yourself on the days you can't.