Is this normal plz

Ok went and got meds (antibiotic) for uti 2 days ago no pregnacy test because my period wasent late well I just tested and positive i am having alot of lower back pain like alot I plan to try and get into to my ob soon as possible had to go to urgent care for uti no spotting or anything also I have 2 other kids and have never had this but.also first time having uti while pregnant the antibiotic im on is safe thank goodness but wondering if this back pain is normal