If you took astrong sea sickness pill as soon as you left the English Channel and took a further one in the allowed time, you ought to be okay. Then lie on you bed and try to sleep.
I take a travel sickness pill and wear the wrist bands for motion sickness, it seems to work for me. Also ginger is good for nausea, you can buy ginger capsules that settle your stomache or take some ginger biscuits with you. These all usually work for me.