I Had A Baby Via C-section A Year Ago. I

I had a baby via c-section a year ago. I never had a problem with incontinence until just recently. I had the birth control implant nexplanon implanted in my arm on December 5. I have been on my period since Christmas Day and it is now February 2nd. Ever since I started my period I have been dealing with incontinence. Today when I took my tampon out I noticed it was filled with a clear fluid and smelled like urine. What I think had been happening is every time my tampon fills up with urine, urine leaks out from the tampon and I pee my pants. This doesn't happen when I cough or sneeze. What could cause my tampon to fill with urine? Is it the nexplanon?