October Menstrual cycle is so strange

I've been ttc since August, that's not the problem, I know it takes time but I am worried about my menstrual cycles. I've never had issues with lateness or bleeding between periods. However, I spotted last Tuesday, it went away, then bled dark brown for two days, it went away. And just got Af on the 11th, stopped after 3 days and now it just came back full force. Has anyone ever experienced this?? I tested twice, both negative.