Spotting Yellow/ brownish discharge

Hi, i am 5+ weeks pregnant. My doctor kept me on progesterone, and baby aspirin as i have history of recurrent miscarriages in 2018. My doctor tested my hcg levels at 4 weeks and it came up doubling for every 48 hours. This morning suddenly i noticed a pale yellow to brown discharge and i am terrified as its weekend and cant really talk to doctor. I am not sure what is happening. I heard taking progesterone prevents miscarriage but is it still possible to spot even with progesterone supplements?