I used to play LS alot back in june-july 2010
Just logged on for the 1st time again and i have no idea how to level
I dont see the regular arena, just the pvp arena.
Did they change this or am i doing something wrong?

It has changed since the last time you logged on. Leveling is now down in the catacombs. Hit the catacombs icon for a solo run, or hit "f" then create a group to run with a group or you can wait for a catacomb group to pop up.

Wow thats kinda lame
I got back on LS expecting to run some solo arena and maybe join a guild when im ready to MQ
I was also confused about the reset and deleted my main that had all my start gear T_T
didnt realize you kept your items after a reset

If you have at least average gear you can play catacombs solo but at 55+ I wouldn't recommended it.
with 1 person in the game the most amount of monsters I have seen at once is 4 but I haven't done it in a wile so it might be more or less now.
you can still solo though at low levels easy enough.

i soloed 55-71 last climb and got 1-2 normal mobs .. upto 3 if evil's .. so if you are only walking on black when u have found a line to walk you will have max of 2 mobs

Thanks!
Good to know.