I can't imagine what could cause kidney pain like that, other than organ damage. Not to scare you, but that could be very serious and I would not put it off. Do you have insurance where you'll be on vacation? Can you get to a general physician or ER where you're going? If you really can't access a doctor until you get back, don't take supplements. Don't drink alcohol (or if you do, keep it to a very low amount, like a couple of glasses...no binge-drinking) and don't take any vitamins, Tylenol (which is extremely hard on your liver if it is already damaged) or anything until you can be positive that your liver and kidneys are working! Your liver breaks down alcohol and most medications, and your kidneys get it out of your body- if either of those are damaged, taking something even as typical as 5-HTP has the potential to put extra stress on your organs and cause further damage.
Afterlyfestyle had some awesome advice and I agree with what he/she said! You're doing great- the body takes a while to recover, but keep doing everything you're doing! And once again...see a doctor ASAP. These are major organs and they should NOT be hurting for this long.