Passing clots can hurt like hell. I get that quite a lot when I have a particularly heavy AF. I don't want to worry you but I had pains very very similar when I was MCing but I was around 8 weeks. I would get intense pain then pass some blood and/or clots then they pain would go then repeat. I have just been diagnosed with IBS which can cause similar cramps too. In fact since I was last preg I have been getting cramps and would then pass blood/cm again my doc didn't seem too fussed she gave me codine and something that soothes the intestinal tract, but I've stopped taking them as tmi they make my poop funny pmsl, but I'll star them again if the pain gets bad at the moment it's manageable.