A few of days ago I started having this pain behind my belly button, almost liked a pulled muscle or a bruise. I didn’t think much of it, but I’ve also felt a bit nauseous and have been getting a lot of side cramps when I’ve been working out, or even just walking. Yeasterday I started my period and I haven't been very hungry lately, which could also be a part of it. None of my symptoms are particularly painful, just constant and distracting. I don’t know, is this typical?