No duh, right?
"Love yourself as well" is not meant to convey "Love yourself too". It is written with the intention that you love yourself as well as you love the person for whom you care. Think about that. How often is your caree on your mind? Constantly, right? Even when you are doing something that is not directly related to them, they are in your thoughts. Imagine if you flipped this reality and in place of your caree, your thoughts went to yourself.
Let me give you an example. So, you are in the middle of feeding lunch to your caree. Normally your thoughts are focused on chopping the food, making sure they aren't pocketing the food in their cheeks, adjusting the portions so they are not overwhelmed, and on and on. What if, in between one of those thoughts, you added one about yourself. Like... What music could I play right now that would make me happy? Or...Hmmm, tomorrow during our meal time I am going begin to have a green juice at the same time to help pump up my immune system.
Where I am going here is that you can care about them and care about you. Be as judicious with scheduling your own doctor's appointments as you are with scheduling theirs. Read up on how to relieve caregiver stress as often as you read up on their illness. Schedule meaningful interactions with friends as frequently as you schedule time for their enriching activities.
It's the one for me, one for you idea. For each nice thing you do for them, do something as nice for you.
It's not an easy metal switch to make. There is the guilt to hurdle over, the conditioned thought patterns to sweep away and the habit of putting yourself on the bottom of the list that you'll need to eradicate. But I dare you to do it for just one day. Just one. Then build up from there.
Love yourself as well as you love them.
And when you are taking care of yourself and allow pleasure to resurface in your daily life, you will be able to love them as well as you are able.