Well, I Just Found Out About A Week Ago I

Well, I just found out about a week ago I am pregnant. (approximately 3 weeks along now) I went to the doctor finally after not feeling well lately and they told me I have one heck of a uti. I have been exhausted without doing anything. I have bad cramps off and on for the past week. No blood. And I also feel that I may be constipated. Is that cause for concern? Should I go to the doctors tomorrow? Even though I am already taking a prescribed medication from the doctor for my uti?