went offroading, now got oil issue and truck wont stay running

[Joey Suburbs]

hi. i recently went out east 4 wheeling, nd now my truck is leaking oil has a very rough start almost like its misfiring, i havent changed my oil in a lil while but it still should b running a lil better, my friend said something about a crank gasket going bad but i cant figure out if thats it, when i drive my suburban i can only go about 40 50, almost like the throttle is stuck, i have oil pressure and my temp doest rise up crazy, i have a 88 v10 seris suburban, 350, throttle body fuel injected, i think this all happend because of the stress i put on the engine, i had to pull one of my friends out of a lake, but its not like i was over revving my engine, if anyone else has had this problem or something simular pls resond back, its my daily driver nd dont have the money to take it to a shop, any help would b great