positive pregnancy test, could it be a chemical ?!!

lisa

i took clomid cd 3-7, my 21 progesterone level was 15.02, i had a faint positive on 11dpo, it became darker, took a digital on 13dpo and it said pregnant! i’m concerned because i had a big temp drop this morning and i feel like af is coming. any advise please. first pregnancy. i haven’t told my hubby yet cuz i’m to nervous. has anyone gotten a positive on a digital and ended up having a chemical pregnancy?