So I'm 16 weeks and 2 days. I've been noticing that I will randomly get a "cramp" (but it's more like pressure and not necessarily painful) and if I touch my abdomen I will feel a big lump that just rised. That's about the size of a very small fist. Sometimes it's not exactly in the middle, it can be more towards the left or the right. And if I touch it it'll eventually go back down. I'm not sure what I'm feeling here and I don't have an appointment till the end of the week. Does anyone know what this is