The two months that were added to the calender were in-fact January and February. If you want some background information on why, then look up the Roman Calender on Wikipedia. Hope this helped!!
If you have no other evidence other than the fact that he has been away? No. If you feel that he's being distant emotionally, treating you differently, or giving any other evidence that he is with...
That you have asked this question shows that there are doubts, and you should only get married if you are sure that it is that right thing and that it is what you want to do. Wait until you know him...
first, if you have had sexual intercourse, you very well could be pregnant. if you are very athletic, that could cause missed period. And last, the most common thing is stress. good luck!