Dore,
1st , avoid Painkillers as much you can ,, and never take painkiller when your stomach is empty ,, its sumthing for the safety of Stomach ...
2ndly, be regular with your vitamins and supllements ,,,, ..
3rd , leg cramps could b due to walking too much .... bcoze oftenly whenever i go out for picnic n Play cricket too much and Runs alot I also Experience Leg Cramps and that sumtimes last for 40+ hours .. so may it could b due to doing too much or more than usual exercise with Legs in shape of walking and running .....
Best of luck for ur exams ...
...
Best Regards
Take Care
Umair