If she is on the pill, it can be making her period lighter and she can have less cramps. The pill is known to do this. (Also if you are pulling out, that's not a no-no if you are monogamous and she's on the pill. The likelihood of getting pregnant when she's on BCP and you have pulled out are super slim, just to ease your mind
)
Ditto to the poster who said we all get cravings all the time, around our period especially, but it's not a huge pregnancy sign.
If you are worried, go on and ask her to take the test but if she doesn't think she is then she's probably not. Most women know their bodies really well....and if you are worried in the first place you will see pregnancy signs in her because it's on your mind.