What you have to remember jacx, is that to those of us who live here all year round, it is a bit cold now, however, for those of you coming from colder places, it's still going to feel pretty warm here. It's all a case of what you are used to. I can't promise there will be no rain, but who can? Looking at the weather we have had over the last few days it's been really hot in the daytime, but cool at night.
As for finding places to eat and drink, yes some places may be closing, and I really don't think this is happening any earlier than in previous years, but you will still find plenty of bars and restaurants open to choose from.
With regards to the diving, I'm not sure when this type of activity carries on til, but the sea is maybe cool, but far from freezing at the moment.
Don't worry, I'm sure you will have a great holiday.