Hi sproutkm,
it's very common for people starting a hormonal birth control to get some kinds of side effects, and like al1234 said, it's because your body is adjusting. Everyone's body is very individual and responds in its own way, so different people have lots of different experiences.
If the pains you're having feel the same or very similar to the ones you usually have with your periods, it's very likely to do with the hormonal adjustment your body is doing, and no cause for concern. If you have very bad pain at any time, though, or these pains get worse, or you have any pain that seems very strange for you and concerns you, it'd be a good idea to check in with a doctor just to make sure, because bad abdomen or lower back pain should always be checked out.
Usually, side effects improve massively or clear up completely within the first few cycles. The usual advice is to wait it out for three cycles so that your body has a chance to settle down and adjust properly, otherwise you and your healthcare provider can't know how your body would respond in the longer-term. Of course, if you're having side-effects within that time that you really can't bear or that are really concerning you, you can absolutely go back to your healthcare provider and ask for their advice. If you're still having side-effects that you don't like after three cycles, it's a very idea to ask your healthcare provider about it. There are lots of slightly different formulations of the pill, and sometimes different people's bodies get along better with one formulation than they do another. Too, sometimes people find that their body prefers a different method. It's pretty common for people to need to do a little bit of trial-and-error to find the birth control that's best for your body.
In the meantime, per the cramps and fatigue: your best move is probably to take as much care of your physical health as you can. Things like getting the right amount of sleep in as regular a pattern as you can, drinking enough liquids, nourishing your body as well as you can, giving your body enough movement. It's not quite the same situation, but some of the general health suggestions in
Stamp Out Cramps! can help when dealing with menstrual hormone-related issues. Do you already use a heating pad?- they can really help with crampy pain!
Does that help you out some? Do you have any further concerns or questions we can help you with?