Need advice

So to start i have been taking doxycycline hyclate since saturday and i think it messed with my cycle not sure though. This is where i need advice cause i was supposed to start yeaterday but didnt so i took a pregnancy test last night and it said negative so i went to bed and woke up at 430am with mild cramping so i went to restroom to wipe and see if there was a period and still nothing so i took another test at 8am and still negative. Could i still be testing early.

(Fyi i have had 2 miscarriages in the last 4 years so im a little anxious when i know i ahouldnt be)