Alymac,
is it normal to see drones in winter?
Not normal but not rare. OK is OK; not OK is likely the end of the colony unless strong enough to get an early laying queen to replace the exixting one.
Little you can do about it now, so assume it is alright and stop worrying because worrying will not make a jot of difference.
With the weather we have had this last autumn and into winter, there may be a lot of colonies retaining drones. It may be your particular strain of bee; they may be a recently superceded queen in there. There may be a queen that is just beginning to fail and she is still laying mostly worker brood. Observe and keep fingers crossed.
I had one colony which had a drone laying queen in the spring last winter. It was no problem to me, but it could be for you (with just the one colony).
Welcome to the forum (first post but been a member a while, I see). A location and hive type would be good as there may be someone local to you to get you out of the problem if, indeed, it materialises.
RAB