How many miles are on it? most likely you have a saggy torsion bar and to temporarily fix it you can jack up the front end and turn the passenger side torsion bar bolt about 4 times (if you dont know where that is, do a quick search on here) that will fix it till it sags some more, which will probably be a few years (if it is your torsion bar).
My friend had the same problem and i though it was the torsion bar so i did that fix and that worked for a few months but then we figured out he had a really bad lower control arm which just finally ripped its self off the knuckle on the hub as he was driving down the road, not fun to end up on 3 tires (Another story soon to come)
But i highly doubt thats your problem because that doesnt happen often, but just to be safe check out the control arms to see if they have cracks in them. But im 99% sure its your torsion bar.
97 Blazer 4x4 4Dr
2" Body Lift, 31" DuraTracs, Steel Bumper, Spare Tire Carrier