stomach bug I think!

So I'm 16 weeks+4 and my morning sickness had finally started to lift but this morning I woke up at half 3 to vomit and have been puking every hour since then. It definitely feels different to usual morning sickness so I'm thinking stomach bug of some sort. The sickness I can cope with as I have been for more than already but it is accompanied with server lower back pain. The pain is radiating from my lower spine/hip/pelvis area then all over my body, it's becoming almost unbearable. I know the stomach flu should pass on its own and isn't dangerous to baby but does any of this should over concerning to you? I also have headaches, and the other usual symptoms but it's the back pain that I can't handle much more of. Has anyone ever had this? What can I do for some relief?