What Causes Spotting And Sharp Pain On Right Side Of Abdomen?

I am 21 years old weight 120lbs 5'5 and on yesterday was suppose to be the first day of my period i had brown spotting all day until this morning around
9 i be gan bleedind regularly. I keep experiencing sharp pain on the right side of my lowrt. stomach but these pains are more sharper than my regular cramps on top of that i get pains from my navel from time to time and my brrasts have been sore since my last period which was on april25