Hello
Well happy valentines day! Notmally I wouldn't say it but is seems like that's what you do where you are from. Valentines day here in Sweden is just like any other day. We also call it Alla hjärtansdag (all hearts day) What we do, well is only that they sell more choclate in the supermarkets in lower price xP and in our school is just any other school day. We do not give each other cards even if it is to a friend or any other gifts and we don't do anything special. This is probably what a typical single and relationship swede do.
Swede in a relationship "hm Alla hjärtansdag, better buy some choclate to gf/bf so he/she knows