Hi Clarissa - stomach pains can be the side effects of Metformin, usually short term though, as for constipation, if your sugars are high you can get constipation with that too.
But do mention your symptoms at your next visit to the clinic, meanwhile I think I would have some of that Fybogel stuff to help you get going, its gentle but effective and not drastic like some other laxative.
I wonder have you considered to take kefir for IBS, some people find it really beneficial and its recommended for diabetics too (see posts by dipsy) and basic info on
http://www.thekefirshop.co.uk, though if you do decide to try kefir I can send the grains for free, no need to pay out for them.
Constipation can make you feel sluggish, or you are just run dow/bit depressed/bg still too high anything like this could affect energy levels. do you take a good vitamin/mineral supplement, cinnamon, etc?
I have times when I am just tired for no real reason, I go out for a bike ride or use aromatherapy oils - grapefruit or any other citrus fruit oils are good for waking you up, but check that you are not allergic or suffer from epilepsy before using oils.
Hope you feel better soon.
Karen x
Challenges can be stumbling blocks or stepping stones, it depends how you view them