Short answers...
Yup, and yup.
Couple of quick questions for ya...
Do you have the hull sitting bow high so it has gravity doing it's thing with the water?
How does your deck (floor) feel? Soft? Solid? Mushy?
My guess is that you'll need a new deck. Also my guess is that when you pull your deck up you'll find foam that needs to be replaced. I would also guess that your "limber holes" (holes right at the middle of your hull ribs that allow for drainage) are all clogged up blocking positive drainage towards the stern. Most of the dudes that hang around here have been down this road.
It's kinda sorta an all or nothing proposition. I am thinking you are looking at a full on rebuild here. I know you mentioned that you wanted to use it for this up and coming summer and then work on it after that. You should have no trouble going that route. Just check your transom to make sure it's not mulch, gotta be safe! Then, when you are ready for a complete tear down, rip out, rebuild - have at it!
A lot of the guys say this around here...
Welcome to the insanity!