My last period I was only on fir a day and my boobs r sore and I keep getting pressure below! Could I be pregnant?

Certainly possible! An abnormal period with breast tenderness and fullness in the pelvis are compatible with early pregnancy. Get a pregnancy test at home or at your pcp's office and check it out.
Yes, see doc anyway! Early pregnancy may cause a variety symptoms: nausea, vomiting, breast tenderness, abdominal pain, vaginal discharge, missed period and/or spotting. Because there is no way to be sure other than to take a pregnancy test, & because some of these symptoms may also indicate another, more serious condition such as ectopic pregnancy, you should visit your doctor.
Yes. The simple answer is get a pregnancy teestyour light period may be an anniversery bleed and your last normal menses may indicate your dates better but get the test done.