You might want to consider something like Neurontin (gabapentin) or Lyrica (pregabalin) to be taken once at bedtime - they could offer help, and I don't think they would leave that much of any hangover at the right dose. Soma (carisoprodol) would actually be great for what you're describing, however there are risks of addiction there, as there are with Neurontin and Lyrica, too, though. But, a lot of people report that Soma retains its sedative-hypnotic effect even after a period where tolerance should have set in, and it is a very good sedative-hypnotic, at least in the short-term; that is, it could do the job. Those are some I didn't see suggested that come to mind. Other than that, I think the z-drug Sonata (zaleplon), as one poster suggested, could also really help you - it has a VERY short half-life. But, I wouldn't discount the so popular Ambien (zolpidem), either - it shouldn't leave much of any hangover, and it can work very well for some. All of these drugs, are of course, sedatives, and do work on GABA - Lyrica is a bit different, but I couldn't tell you much more than that it certainly feels GABAergic, in nature.
Benzo's, that I might suggest - Serax (oxazepam) is not an hypnotic benzo, but all benzo's have hypnotic properties, and while Serax is pretty 'mild', at the right dose, it might be very good for you on account of its short half-life. Xanax (alprazolam), for obvious reasons of potency, speedy onset, and short half-life, and Halcion (triazolam), which is an hypnotic benzo that is very hard to get, but that would do the job, and has a VERY short half-life.
All of the drugs I mentioned can lead to physical dependence with continuous use, and it is no joke with these types of drugs. But, let me say that you might want to try weed again with a benzo or other sedative-hypnotic taken before hand; you might, then, not need as much when it comes to dosing the sedative-hypnotic, and the weed experience would be more tamed out.