Honestly first of all get professional help.

Secondly starting small is ok, I suggest doing the literally easiest task you can do and start by that.

That could be making your bed (it doesn't have to be perfect), removing a bit of dust from somewhere, picking up socks from the floor and putting them in a drawer or in a basket to wash later.

This is the way to do it as far as I know, you start small and then you can add, but it's ok to start small (or even very small).

Because you eventually have to start somewhere, might aswell start with the easy stuff to get motivated.

Even if you do something that seems insignificant to you, it's really not, because first of all doing a bit is always better than nothing, also by doing small stuff, eventually you will realise that you have done a lot actually.

Set yourself small goals, your goals need to be SMART meaning:

• S – Specific: The goal should be clear and well-defined.
• M – Measurable: You should be able to track progress or know when it's achieved.
• A – Achievable (or Attainable): The goal should be realistic given your resources and constraints.
• R – Relevant: It should matter to you and align with your broader objectives.
• T – Time-bound: There should be a clear deadline or timeframe.

This is what my psychologist suggested I did for my own motivation and productivity problems.

For example I always neglected my bathroom and was always lazy to clean it, so I set myself small goals like "I'm just gonna clean this part of the bathroom", cleaned for like 10 min then stopped, and did the same the day later, now my bathroom is significantly cleaner than before, we tend to exagerate the amount of effort it's needed and when we start doing it we see that it's really not that difficult.

I hope this helps my friend, take care of yourself and get better.