So is the IUD Mirena supposed to feel uncomfortable the first day?? or at all?!?

It's perfectly normal to feel a bit odd right after you have an IUD inserted. You may feel cramps, or just that "something is different". Just because there isn't feeling in the area doesn't mean your body hasn't taken notice of an invader. Give it a day or so to settle down. The region is likely still pretty sensitive after having had a baby not so long ago as well, and that's not going to help a lot either. Yeah, I can empathize with not wanting another real soon after having one. That's normal too. I think you are dizzy just because you are a bit worried, a bit frightened, and you've been through quite a bit here lately. Your pinch sensation is probably just the end bit of string giving the cervix a poke. That too will ease up. If it doesn't in a few days, then return to the doctor for a check. Sometimes they cut the string a bit long, and it just needs a small clip job. It's also normal to spot bleed for a day or so afterward. The primary thing to be careful of is to check that string after every single period, to make sure it's still there. You may want to check once a week for the first month or so, as well- if you are going to expel it, you are most at risk the first month and first period. Otherwise, hopefully it will work well for you. Lots of ladies have them and love them. Some can't use them, though. You will just have to wait and see how it goes for you. If needed, reread the information you got, and make a list of the questions you still have. You can ask the doctor, or perhaps his nurse, to answer them.