I can't exactly remember when I had my last menstrual cycle and I have tested positive for being pregnant however I am now struggling with how long I have exactly been pregnant. Irregular cycles is very common for me. I have missed two consecutive months before.

Your ultrasound will give you a better idea. There's really no way for anyone on the internet to guess. Even an ultrasound isn't exact, but it's better then any of us can do.

Yes, its possible. As Altenweg said, your ultrasound will give you the best possible dating.