My period is late, and my breast are very tender. But I have been having "period" cramps for about a week but no signs of a period. I was just wondering if I could be pregnant and still experience cramps .

Yes.
There is NO definitive way to determine pregnancy except a test. Symptoms can mean period, pregnancy, or something totally unrelated.

Yes, it's possible.

It's possible but too soon to know. If you are more than two weeks late for your period, take a pregnancy test with first morning urine. There is no way to read symptoms because they can mean a lot of different things, so don't let your imagination get away with you. If you test negative and still don't get your period after two weeks, wait another week or two and test again. If still negative, go to the doctor and see if they can figure it out.