Talk to Gynecologist on Spotting Since 2 Months

hello. I am married since two years and I am trying to. conceive since September and I have a regular menstrual cycle. my lmp 8-14 Oct and after 12 days I had spotting for 5 days then after 11 days I got spotting again for 8 days and again as usual after 10 days again spotting for 7 days. Now, I got little gap here and so now after 16 days I see few spots today and in November doctor gave me few test to check if I had any infection but my reports is clear so she advise me to take folic acid only and I check my pregnancy test also today but it came out negative I don't know what's going on, as soon as possible I want to conceive. I am really depressed please advise what should I do now?