Worried about a possible chemical

Hi, I got pregnant this july that ended in a miscarriage. Today I am 13dpo and tested positive but its a very faint line. (it is my first test this cycle). I am worried it is a chemical as last time it looked like this at 9dpo. I know I need to wait another 48 hours, but I would like to hear ur experiences. I tracked my opks so fairly certain about ovulation day.