What i thought was a uti

So yesterday I went to the hospital for what i believed to be uti/kidney infection pains. Come to find out i dont have either of those instead i was having contractions 5-6 mins apart. They tried fluids to stop it and nothing worked. They gave me a shot to stop it and it did for like 30 mins, but they came back looking more like irritation not contractions so they sent me home. I have an appointment tomorrow to see if i am in early stages of labor. Fingers crossed its not i am only 28 weeks and 2 days. I never experienced this with my other pregnancies so im nervous as can be.