Why weren't my period normal?

Ok so i was due for my period on the 23rd i got on the 24th.. they where never late till now.. i had on april 9th(PROTECTED).. when i got my period it was more spotting then period.. but i have this bump i feel it's in ovaries parts... it's very painful in the back and in my belly.. i have so much nausea.. but people keep telling me i can't be pregnant.. i am so afraid and stressed.. i work in a daycare and i am 17..