While being consistent is a plus point, many things do not allow you to be consistent.

To be consistent, here are a few things that can work out for you:

Doing the bare minimum and keeping a maximum limit to what you can do.

What does this mean?

Every day you decide the minimum thing you will do.

For Example:

I will code for half an hour, 
I will revise for 20 minutes, 
I will think about this for 5 minutes.

That minimum thing should be something you should estimate that you have the time, energy and resources to do. And do the bare minimum every single day.

Once you have done a bare minimum, decide on a maximum limit to avoid burnout. Okay, I can sit to code for a maximum of 'x' hours at a stretch, nothing beyond that. I have to take a break of at least 15 minutes after that to make sure I am okay.

What the minimum limit setting does is:

You every day do something. It allows you to comfortably continue what you like.

What the maximum limit setting does is:

It allows you to monitor what is not feasible to keep doing considering your physical and mental health and at the same time allows you to function to your best capacity.

The correct minimum and maximum estimate should be decided by you itself. With time and practice, you go about this effortlessly.