Wow, props to you. I think it took me a good 3 or 4 months to get through Infinite Jest. I think I enjoyed it overall, but I have yet to feel any desire to pick up another DFW book. When I do eventually get that urge, do you have a recommendation for what to read second?
If you're feeling a barrier, I'd pick up one of the short stories books. Girl with Curious Hair was a great second read for me. It's unabridged, got a lot of strange stories, and ends with a short novella that's a decent precursor to IJ and has similar themes. From there, you can either opt for non-fiction / essays (Lobster, A Supposedly Fun Thing, Both Flesh and not), more short stories (Oblivion (very dark), Brief Interviews), or either of the other two novels (Pale King, Broom of the System). It took me a while to approach Pale King, but after the first many insufferably boring chapters, it suddenly becomes much more engaging and an interesting read.