Persistence Pays off, or doesn't it?

Last month's IUI didn't result in pregnancy. Instead, I had spotting from day 23 of my cycle until the progesterone suppositories couldn't hold it anymore and my period came, one day before I was supposed to test for pregnancy. So this month our second IUI was on May 2. Everything looked great. My husband's numbers were great, my numbers were great, my uterus lining was "fabulous", and I even had some spotting 5 days after the procedure. Could it be a sign of implantation? Then, a few days ago, I started having cramps and some pain on my lower back similar to when I'm about to get my period. I've been testing and, so far, it's negative. Not even a faint line. I'm supposed to test this Wednesday, 2 weeks after the IUI, but I think I already know the result: not pregnant. Saturday morning, as I drove to church, I sobbed bitterly, in the safe refuge of my car. I hadn't cried that hard for a long time. My antidepressant is working wonderfully, so I feel pretty well, but the pain of not being pregnant AGAIN was too strong this time. Some may say I'm suffering in advance, after all, there are still 2 days to go, but sometimes you can just feel it, and as much as I want to be pregnant, I don't want to build up my expectations over negative tests and cramps from the past 3 days. It is clearly not happening this cycle. So in my mind I know we have to be persistent, we have to be patient and move forward. My husband always says persistence pays off. I so want to believe that. Today, though, I wish I could see the light at the end of the tunnel. I'm sad, discouraged, frustrated, tired. I need a best friend's hug, a good cry, a reason for hope. I need to hear from someone with authority that it IS going to happen, and happen soon. I just need to be patient - and persistent - and it will pay off someday. My question is: when? And can I endure the wait?