Yellow discharge??

So I went onto the nuvaring for a month (it’s my first time taking birth control as well) and experienced an increase in discharge with a strong smell I wouldn’t say fishy but acidic. I didn’t let my boyfriend have sex with me (for the whole month of being on birth control)since i was shy about it...took it off for a month and I still have this discharge what could it be? Is it normal? Was it Bc of the birthcontrol? Some days it’ll be strong and some days it won’t..also got checked in January if I had anything & came out negative so what could this be?? I also know the ring is supposed to make more discharge but I don’t know about this color..