I hope you don't mind the sad ending... or at least it's supposed to be sad. FYI that card was supposed to technically be platonic. Lily signs everything 'Lots of love'.
I can barely type right now, I worked on two comics this weekend... one is a Lily/James one that won't be posted until the 23rd, and then there's this crud. Just try to ignore all the mistakes, I just scribbled it on my tablet.
PS: Snape is really just mad because Lily got a ton of valentines from boys. James and Sirius also cleaned up pretty well, as you can see.