Question Question Question!!!

Ok so i’ve noticed that at certain times, especially after my period, on my outer labia that there’s light yellow greenish pasty like stuff there and i’m like do i have a freakin STI or is it from hormonal changes because it goes away after a certain amount of time then comes back. i don’t have any itching or burning or burning while peeing sensation but i do have sensitive skin and try and stay away from scented soaps. I was just trying to see if it may possible be a STI but i haven’t had sex in over 6 months and i’ve used a condom for the most part. I didn’t really notice this when i was sexually active until I really got into my sexual health more so.