My Periods Have Been Irregular For A While But For

My periods have been irregular for a while but for about a year now they have been regular as in having one every month I am sexually active and may have missed a period in July my period cycle days vary widely each month so I'm not sure . but I think it was supposed to be around the last week of July but it never came im not sure how many days I'm late but I think around ten could I be pregnant. Took ept and got very faint negative line am I testing too early ?