1996 Suburban 2500 with plow problem-PLEASE HELP!

We own a 96 suburban and we have been plowing with it for the last couple of years. this year we were getting the truck ready for winter duty and noticed that when we hook up the plow to it, it sinks really low. it used to do it just a weebit before but now it is definitely more dramatic than before.
what could be the problem? is it our shocks that are bad...? the truck sinks significantly when the plow is hooked up- someone please help!

Welcome to AF, cylinders are not holding the hydraulic presssue or you have a leak somewhere.

Thank You for the welcome.
when talking about the cylinders you mean the shocks, correct? as far as I know, they are the stock shocks that have been on the truck since it was new.
So my option would be to change out the shocks correct? and the leak would concern the suspension also right?

Thank You for your help.

I thought you meant the plow sinks down. If it is the truck itself, the springs are weak not the shocks, If torsion bar suspension, bring them up a few turns.