Mirena Day 4

So I've had mirena for four days now and I just wanna make sure cramping is still understandable to have? Right? And like kinda constipation feeling? It's weird but I drank about 5 beers the other night and think I dehydrated myself because the next day my back hurt and I had cramping? Is this normal? Someone explain a few things so I have an idea of what's going on