morning sickness

I am 6 weeks into my first pregnancy, I have had terrible morning sickness throughout the whole week, especially yesterday, I was sick all day. Today though, I feel completely fine, no nausea, no vomiting and only a slight headache. Is it weird that feeling okay has me worried? I feel as though I'm overly anxious will go wrong and it may be silly. But, I guess I had gotten used to feeling so cruddy that now feeling okay I'm like "what's going on here"? Anyone else have this experience?