AmE speech typically mixes up lay and lie.
"I may just go lie down on the bed"; the action of a person is: lie down
"I will lay your clothes on the bed when they dry.": what you do to a thing
In colloquial American speech, lay down is used for lie down. It is marked as dialectal and probably uneducated speech. (Uneducated speech does not mean I am judging it here. I am not.)
Lying down on a bed can make you feel better if you are not feeling well.
Laying your clothes out on the bed on a chair is a useful way make your mornings easier.
Please note the verb forms:
I lie, I lay [yesterday], I have lain [gerund: lying]
I lay, I laid [yesterday], I have laid [gerund: laying]
There are many sites on the Internet with exercises for these verbs, which many people do mix up, even native speakers.