Although doing some Post Process effects like others have mentioned could definitely add to the effect, I think the visual vibe you are looking for would be more easily replicated with a very slow moving Camera Shake. There’s a quick but thorough tutorial on it here. The main change you’ll want to make is slowing down frequency of the shake so that it appears more like a loose, random sway. Play around with the settings until you have a base motion you like, then I’d start adding in addition Post effects like fringe, grain, vignette, and maybe even some motion blur.