Bleeding aft missed period pregnant?

Hi, we are planning for pregancy. My cycle is regular and it is normal for past 3 months as i am tracking it. My cycle duration is 29days on average of 3 months. my previous period is on 30-Mar-2019. I was expecting my periods on 30-Apr-2019  (day32) but it didn't happen. We thought to wait for few more days before taking pregnancy test. But on 02-May-2019 (day34) early morning i started feeling little cramping and bleeding. Initially i thought it is a period bleeding. But i didn't had any symptoms of my regular period. Bleeding also.very less and it only lasted for 2 days - day35.  Color also brown. We taken the pregnancy test after 2 days once bleeding stops and it is negative - day37. So we decided to wait till 2 days and checked on day39 but still got the negative result only. Already i am taking thyronorm 25mcg and also folic acid for past 1 year. Becoz exactly an year back i came to know i have little thyroid issue. We got married a year ago. Please anyone advise wat to do next??