Sore nipples, what could this mean?!

Recently (as in the past.. week I'd say..) I've noticed that my nipples have been very sore/tender. Not my breasts, but just the actual nipples. I've already gotten my period and the next is not due for another week or two. I'll admit to having a little "rough play" with my boyfriend but usually if they're sore afterward it's only to the extent of a day - if that. I haven't seen any changes in color (as in they're getting darker, etc) but it was just out of the blue! At the same time I noticed myself wanting to eat more even when I wasn't hungry, lack of motivation to get up and around due to feeling more tired than usual, more frequent headaches, feeling slightly nauseated here and there but its minor, cramps like I was going to get my period and haven't, and an increase in sex drive (major increase). I'm not quite sure what to think or to make of it, and to date, haven't been to the doctor or taken a home pregnancy test to eliminate the possibility that I may be pregnant. To be honest, I'm slightly afraid to know this answer. Any advice?