Was this a chemical

Last cycle I was trying to get pregnant and I took two dollar tree test they both came back with a faint positive! I was going to test the next day but my period started. It wasn’t like a normal period. The pain was unbearable and when I went to the restroom and I wiped there where clots which had never happened. Was this a chemical pregnancy and for anyone who has experienced this was your next period late mine is 13 days late hpt negative and blood test negative so I’m not pregnant what do you think?