contractions??

Ok so this maybe the DUMBEST post ever, but I'm actually concerned about this. I have no clue what I'm supposed to be waiting for with contractions. what do they feel like??? I understand they're tightening of your uterus but, isn't my uterus my whole tummy at this point? I've been getting stuff that feels like period cramps, is that it (or at least Braxton hicks)? Or sometimes it feels like kicks down in my vaginal area but it almost feels like she's actually kicking it (I know that sounds super dumb). I also get really shap pains in my tail bone sometimes.. is that what 'back labor' is? am i getting braxton hicks in my back??? any advice on how to tell what contractions will feel like? Or any explination on the other feelings I've been getting?