HELP!! worried about pre term labor!!!

So for a week now I have been having really severe back pain to the point where I can't walk lay bend down or anything it's only in one spot on the right side of my lower back I went to the hospital last night and they sent me right to labor and delivery put me in a bed the doctor came in and said I had blood in my urine which means a UTI but the problem is this is my third UTI since I've been pregnant I'm 22 weeks and have taken meds twice already( I am now taking a 3rd dose) and it doesn't seem to go away the doctor said I could also have a kidney stone and have to go for an ultrasound on my kidneys within the next few days she also said that she reviewed my last ultrasound and my cervix looked thin and short She also said that UTIs are the most common reason for pre term labor so now I'm worried that with all these factors I won't be able to carry my baby full term 😓 Has anyone else had these problems and were able to have a full term baby? I'm very worried