Could i be pregnant?please help!!!

Yesterday i thought i was starting my period because i started having light brown blood not much and then i started having red blood but it was on and off and very light. I remembered that i only had my period at the beginning of this month, so it seemed wierd if i was already having another one. Im not having much red blood at all and when i am its quite a bit but its on and off and im having quite alot of brown blood. The other week i also noticed i had like clear mucus.
Me and my partner always use condoms but sometimes before we have full sex he puts it in me without nothing on but he never comes in me,although i know there is still some risk from this.
Im beginning to worry i could be pregnant, what do you think is the possibility? Ive also experienced cramping and lower back ache.
Please help!!