I've been veggie since the early 90's.
I can't really comment on Spain as I've never been, but I can perhaps clear up a few myths.
The big one is that I think it's possible to have a healthy diet, or an unhealthy one, irrespective of whether you eat meat or not. If your diet consists solely of Big Macs, or solely of lettuce, you're going to be ill. Whichever you choose, try and get a balanced diet.
If you want to give it a go, it doesn't have to be an all-or-nothing thing. Do it gradually, and see how you feel. Maybe cut out red meat for a few months, see if you're happy, if there's any side-effects. Then if you want to carry on you can look at removing white meat and see how you get on there.
If eating out is a problem, perhaps you could go veggie at home but keep meat as a "treat" when you've no other option?
Both veggies and omnivores have their share of evangelists. Ignore them, they're invariably halfwits, and the problem with discussing things with halfwits is that they drag you down to their level and then beat you with experience.