Pain in my abdomen

I'm 17 weeks and 2 days pregnant and I've just started experiencing some abdominal pain. I've had mild stretching pains and cramps before and I was never worried. But this is more of a dull pain in the centre of my abdomen quite low down. 
Just wondering if any of you ladies have had this, or if it's just stretching pains perhaps? There is no blood or spotting at all. 
 Any advice is greatly appreciated. This is my first pregnancy so there are still a lot of things I have yet to understand ☺️