Yes, it was a bit bittersweet. But we all know Harry, right? So we know that he will do everything to be with Severus, to see him smiling. I don't need a sequel to this, I can say what was next:
One Friday Harry went to Severus' room with a bottle of good Firewhisky and said "Hope we could have a great weekend together". And they had. Not only weekend but all live.
The end x)
Hugs,
myk