constant spotting

My last period lasted about 18 days (longest ever, this is unusual for me) but it was just brown spotting. After the 18 days I had a regular period with red blood for about 5 days but now the brown spotting is back? It’s really minimal but it’s still so annoying. I got off birth control about two weeks ago because of it but the spotting hasn’t gone away. My vagina is also slightly itchy but I can’t tell if it’s a yeast infection because my discharge is brown, not white. what should I do?