First I totally agree that you should get this checked out, rule out things like appendicitis etc, etc.
However there are a few really simple (free/cheap) things you can do which may help. I am not a dr, but my daughter has just been through some really bad health problems caused or causing (chicken & egg problem) stress/anxiety & constipation. A couple of the things he has suggested for her (she's 15) are: to take a gentle 30 minute walk between 6 & 7 am every morning (unless the weather is absolutely horrid) as at this time there's something in the suns rays (even when it's cloudy) that affects chemicals in our brain & destresses us. Also eat foods that are high in tryptophan which also balances the serotonin levels in our brains & so destresses us, tryptophan can be found in lots of things, most nuts, turkey, bananas, plain yoghurt, pumpkin seeds & tonnes more.
Also with stomache pains you might try working on your large intestine by firmly rubbing it to help move "food" through (often stuff gets stuck there & can cause cramps & lots of other problems) you start where it starts - lower right groin & move in a straight line up to just under your ribcage then across & then down to your lower left groin - keep the motion of your hand firm & basically slow. This has helped solve a problem with constipation that my daughter has had since birth & nothing else has helped.
Next, you could try rubbing a stress release trigger point - on your wrist directly down from your small & ring fingers - firmly up & down for about 2-3 inches; lastly if you have a headache rub firmly on the "lumpy' area of skin which forms where you hold your thumb & first finger together (you can do this without holding them together this description just helps you find the area in the first place).
Hope this helps, but do see a Dr. Oooooops just thought of one more thing, sometimes we develop allergies to food as we grow up just like there are foods we wouldn't eat as kids & then love when older. So consider whether maybe there's anything that you eat/drink at night or first thing in the morning that might be the cause. I used to love lettuce, bananas, peppers/capsicum & cucumber now I can't touch them without serious stomache cramps (can't even have them in with other foods) my daughter is the same with banana but loves the others & in fact finds that eating lettuce will help her if she has an upset stomache!!
Good luck
