missed heart beats

I've been getting missed beats daily from the day I stopped drinking very heavily every day for 2 years (as well as taking diazepam). I stopped drinking completely, cold turkey 8 weeks ago but continue to take diazepam for anxiety, and to control any alcohol withdrawl (withdrawal) syndrome.

My question is why is it that the missed beats only happen from about midday? I get up at 6 am daily, and have no episodes till midday or so. Then, they kick in maybe 1 every minute, then ease off after a few hours until at night, I have 1 maybe every hour.

Some days, I'll get no missed beats till 3 or 4 pm.