What Causes Spotting And Sharp Pains On Lower Side?

Hi, i am 21 years old, female, 5"5 and approx. 9 and a half stones. For the last four days i have had spots of blood coming from vagina, however its not excessive blood and im quite certain its not my period. Also i get sharp pains on my lower right side, below my rib cage when i laugh. Any ideas what this could be?