16 years of cycles and now nothing!

Okay I dont post much, any insight from anyone helps. So I've gone through life pretty normal with my cycles as far, one every month, cramping, and junk yada yada. I'm am 24 now, and have not had a period since April, I've taken 4 pregnancy tests all negative. I've seen 2 doctors so far, one was an obgyn he told cervix is fine, did a pap test and did the finger exam and some educated guesses. I also had a UTI 1 week after my period was late, the OB guy gave me 2 prescriptions. One for the uti and one to jump start my period again.

I have finished the antibiotics, but have not touched the other one, he said if I wanted to wait I could, but beyond the pelvic exam and the pap test he did nothing else. Second Doctor I did a full body exam, he did some blood work and order a follow based on whatever results come back. I brought up the idea of PCOS, my olde sister told me she had it and advised that it's possible I could have and should be tested for it. Second Doc did not believe I needed an aultasound or felt that I had PCOS as he figured I would have found out a long time ago. Me knowing my family and upbring when it comes to anything medical, unless your passed on the floor and bleeding to death, you don't go anywhere. I would never know, hell if I do have it I probably think this is normal and never questioned any of my month to month experiences, but hey doc knows best.

The only stress that have had was, after all the urine tests came back negative, my cycle is anywhere from 27 to 31 days on average, I've been with my husband 3 years, and we still have not conceived. I've have never had to dues any birth control let alone any time of medication for anything or than a UTI. I do not want to spend my life on hormonal drugs, is there anyone else in this boat with me?? Any ideas help.