I have been drinking quite a lot for quite a while (2 thirds of a bottle of wine every night.) Over the years I have had the odd night or even 2 off a week to try to keep levels down. Not always tho. Anyway, have not had a drink for 4 days and since yesterday I have had a stonking headache that painkillers don't shift, I'm not sleeping well, and feel worn out. Apparently I look pale too. Could this be some kind of withdrawl? 