Why do I still wake up felling rough after cutting down on alcohol and other things?

Hi,I was drinking on average 14 units of alcohol on week nights and a lot more at the weekend also I was smoking weed on a nightly basis. I have now given up smoking weed and cut my alcohol intake down to about 8 units a night. I did all this on the same night and have kept to it for about 4 weeks now. What I'm wanting to know is why am I still waking up feeling rough even after a good nights sleep?