Im in Dunyun Laboratory and in place where you have to swim to get out, but im too slow and there no time to reach another end of the pool, so what do i do? do i have to swim around the pool surface to raise my stat or what?

When you're about to drawn, cast your Water Breathing spell. Even if it doesn't last very long, it will at least reset the timer.

Aint got no spells yet and cant find hidden doors or nothing. I started the game for first time in my life couple of days ago. AM I F***ED?

Then what are you doing exploring dungeons (other than the one you start in, of course)?

Anyway, you can warp to the start of the dungeon by loading your save and then immediately pressing Alt-F11. Cheat mode is not required. (This can also be used to skip the tutorial.)

If there were a "comment of the year" contest, I'd nominate this one! :-)

But seriously: Daggerfall's dungeons are unpredictable - you never know what you find inside - and sometimes the time limit is a challenge, too. Unless you are prepared to accept the consequences, you better save before entering a dungeon and remember ALT-F11 (if you get stuck and don't want to start the dungeon all over again)! Have fun!

If you didn't have to swim to get in, you shouldn't have to swim to get out. ;)
Seriously, I'd recommend looking for another way out (the dungeon map will be helpful in this...just make sure to use the top-down mode, not the less useful iso view). Try to just retrace your steps, if possible. If not possible -- e.g., you fell down a hole and the only way you can find to get back to the entrance is to take another route where you have to swim -- then, without magic, you may be stuck using the "cheat" already mentioned.
A couple more thoughts: 1.) Climbing can be a very useful skill to practice/train for use in dungeon (and town!) traversal, especially for low-/no-magic builds -- it might or might not help your current situation, but it could be quite helpful in the future ("Help! I fell down a well and don't have levitate!"); 2.) IIRC, there is such a thing as being too heavy to swim well. Try lightening your load and trying to swim out again.
(Apologies if this advice comes too late to be of any use.)

And, contrary to what the others say, you don't need to be a spellcaster (though you will need magic in some form, so if you're going to eschew casting, you'd better start stockpiling enchanted items and potions). The game will be a bit easier if you learn (and practice) at east a couple basic spells, though -- Recall (or whatever it's called) being one of them. And either way: save early, often, and in multiple slots (i.e., rotating saves -- but always keeping at least one or two from before you entered the current dungeon, when you're in one, or accepted the most recent quest), just in case. :)