Time to say goodbye

I am in year 10, my ex/close friend is in year 11, she leaves school in 4 weeks, i still have a year to go, we have been through so much together, i have helped her with things she couldn't go to anyone else about, but before the holidays she started going in a mood with me and her friend say leave her alone. I go back in less then two days and its the last half term with her. I think i should stay away from her to make sure i'm not too upset when she leaves. Should i stay away or stick by her and try to make things better! PLEASE HELP!!!