Awful cramps and need to go toilet @ 26 weeks

Does anyone else get really bad cramps and then need to go toilet almost immediately? 
I've been getting them in my lower abdomen and it is like a 'need to go to the toilet' pain. Sometimes I go, sometimes I don't but are these common? 
I've been getting them for a few weeks so I'm assuming it's all normal in pregnancy but the pain can have me doubled over sometimes.
Anyone else experience this or something similar??