Do Irregular Periods Indicate Pregnancy?

hi i been having unprotected sex and i think im pregnant. last month i had my period normaly on the 3 or 4th and then i had another wierd period the same month on the 20 i think and it was wierd because it came in the morning and then it stop at night and i didint have it in the morming then it came again and it stop and i continue like dat for like 3 days i think and then this month when i was supposed to have my period but in he 3 or 4 it didint came and i think im feelig pregnancy symptoms but i dont know ineed help