We can't tell for sure. Cramping and spotting is normal in early pregnancy. If it's painful and the bleeding is getting heavy then that would indicate miscarriage. You need to still see a doctor though, especially if you have the mirena fitted. You're more at risk of ectopic pregnancy because of this being fitted.
You are at an increased risk of an ectopic pregnancy when you get pregnant with the IUD in place. Your cramping and bleeding are also suspect, so I would urge you to call your doctor tomorrow morning and explain this to them. Good luck
its hard to say have you been to the Dr? cramps and spotting are normal at the start of your pregnancy. i had spotting for the first 12 weeks everytime my period was due. Go and see a Dr if nothing else they will be able to put your mind at ease, Good luck i hope everything is fine