Why did i have early light period? and why did i have strechy discharge a day after it ended? could i be pregnant?

Possibly: Its always possible. Take a home pregnancy test. They're accurate, valid and reliable if performed correctly. If it's negative, repeat in a week and call your doctor.

Possibly: Some women have implantation bleeding, which may resemble a short period early in pregnancy. I recommend taking a pregnancy test. If it is negative, track your cycles to see if they are becoming irregular.