Literally:
Merci pour tout,
Tu me manqueras ce week end.
But it depends to whom you're talking to.
It's OK if you're talking to a friend.
But if you're talking to a woman you're in love with, don't say her "Thanks for everything". I'm quite sure she won't like that. Better to say: "Je n'oublie pas ces merveilleux moments" (I keep in mind these wonderfull moments).
Also avoid the "week end" thingy as she might understand that you'll miss her for the week end only (yes, women are like that, at least the French ones are ). Better to say: "Tu me manques déjà" (I already miss you).
Hahah it's ok, the words are part of the joke, as I forgot to tell her ages back that I wasn't around for the weekend, and she found out from the note on the flowers lol... whoops
). Better to say: "Tu me manques déjà" (I already miss you).