Cartwheel help please answer quickly!?

I'm a tumbler, and I'm AWFUL at cartwheels and handstands. I've been in tumbling 4 three weeks, and all the other girls are sooooooooo good! When I do cartwheels, I land on my or my feet but in a squatting position. What am i doing wrong? Plus, when i do handstands, i flip my legs over my head and land on my head! PLEASE HELP I HAVE CL TOMORROW! Thanx!