I was sick and I used that excuse to be lazy
Why would you use being sick as an excuse?
I never want to go to work or school when I feel a little bit under the weather
If you are not legitimately sick, then you should not let other's believe that you are. Behaving in a lazy way is not a good trait to have and you will never benefit from it.
I'm going to lie to my parents that I was in the hospital. What are they going to do?
They might freak out if you tell them something like that. Telling people that you are sick, just because you want to be lazy is not the way to go. You should just be honest.