I do not think that a tilted uterus has anything to do with your ability to conceive. I would make an appointment with your doctor in the mean time to discuss all this stuff, it is a good idea anyway to start out the TTC journey with a pelvic exam and pap.
The really bad menstrual cramps you have are most likely do to your tilted uterus, I have heard that there is a correlation between the two. This would also be something to double check with your doctor on though.
The cramping you are having could mean different things depending on what day of your cycle you are on. It could be ovulation pains if you are around ovulation, period pains that are a little different than usual, or pregnancy cramping. It also could be lots of other things.
I am sorry I could not be more help, but I think that you are fine and are probably just over analyzing everything, we all do it so don't feel bad.