Guilt, as with all of your feelings, lets you know there is something to which you need to attend. Feelings are like road signs: they let you know of curves ahead, yield, or another warning. You don't park our car by these signs; you respond to them. If you don't, you crash. This is true with your feelings, too.
How do you know what is a healthy amount of guilt, and what is too much?
On the positive side, guilt helps to regulate your behavior, and drives you to make amends when necessary.
On the negative side, guilt or even the fear of feeling guilty can be overwhelming, and keep you from doing healthy things for yourself.
If you experience a lot of guilt, I encourage you to ask yourself what it's related to. For example, is it related to self-esteem and confidence? Is it related to a religious upbringing? An over-bearing parent?
I've noticed that many adults don't do very much self-care (exercise, time alone, time with friends, and other activities that rejuvenate). I've been told that between family and work, "Taking time for myself is selfish or would be frowned upon by my partner." Yet many partners say they want their partner to have friends and do things that bring them home in a great mood. It's infectious, and brings joy into the household.
Create a list of healthy things you would do if only you wouldn't feel guilty. Talk with your partner about this and let him/her know you're going to do an experiment. Maybe you figure out together what a few good times are to do something you want or need for yourself. Let your partner know well ahead of time, so you are not springing it on him or her. (Realize that your list right now is likely different because of Covid-19 than it will be later on.)
Go do it. Notice how you feel before, during and after doing this for yourself. Try more than once to give it a chance to work. At first, you may feel odd. This is normal. Doing healthier things is going to feel abnormal or wrong if you are not used to it.
What can you do, if, after experimenting, you still are consumed by guilt? Try this: In your imagination, gather all the guilt in your body and mind and place it in a big box. Close and seal the box. Tape it up well. Shrink wrap it. Place it on a shelf in a closet. Close the door. Imagine yourself walking away. Please know that if you want it back, you will know where to find it.