Help!!!

My last period was on May 2. I have another app that say I was suppose to come on again on May 29 but didnt. This app said June 4 and didn't either. I took 2 test one on June 1 and other June 11 both was negative. Here it is June 19 and still nothing. I have cramps and back pain. With my first born I didn't get a positive test until I went to the hospital and they did blood work and found out I was 6 weeks. Should I just got to the health department or hospital and ask for a blood test? Because with my first I was 4 weeks and the doctor urine test came back negative and they said i had a UTI. I really need help....