I’m not completely adamant on taking the pill right now, just trying to find one that works. I’m on day 2 - How long until I start seeing side effects?

I’m breastfeeding and taking a low dose combo pill so I will stop if it affects my milk supply. My question is, when would I notice that effect (or any in general)? And how soon after dropping would my milk come back (or for any side effect to stop)?