I need you ladies!!!

I will be 18weeks on Wednesday.. and for the past 4hrs I have had a constant sharp pain on my lower left side and into my back.... it hurts if I move or sit straight up... even bumps in the road while driving ... I have laid down.. stood.. sat... and nothing is helping I was running my stomach and I noticed n knot in my lower stomach about the size of my whole hand like tip to bottom of Palm.. I am tryin to wait it and and see if it stops ... or should I go to hospital just to get checked out? What do y’all think ?