All day sickness/headaches... Can't do anything?

Natz
So I'm about 11 and 1/2 weeks pregnant and last week I started getting really bad nausea and headaches, so bad that I can even get out of bed! It's a nightmare, I've never felt so ill before. I was sick about 3 times and constant feel unwell, I never had this with my first 2.
​Does it mean anything and is there anything I can take to help?
​Thanks