Hi Reena, and welcome to the forum.
IMO, it would not be worth it for you to do a gluten challenge. Why go through that when you have already had success with going gluten-free? Fertility problems and migraines are linked with celiac disease or intolerance, and so are a number of other things you mention. I can't address the blood tests because I'm not qualified. But I see a few doctors and they all agree the blood tests are not reliable at best.
I don't know if that's good advise or not, just saying what I personally think. I was not willing to undergo a gluten challenge after my blood tests came back negative. I really couldn't justify the risk/reward benefit. Validaton? I already knew, and it was a long, hard road to get there, just as it has been for you.
Good luck to you,