On the pill.. Spotting instead of period?

I'm on loestrin 30. Over 2 weeks ago I started antibiotics. Had ovary pain- also had sex those days to. I spotted a bit after a week of sex.. So I have my period week now and no cramps or bloating just spotting... The tampon hurts- I guess cause not enough blood but I'm scared that it's gonna go heavy so I keep putting another one. All day everytime I change tampon there's like a penny suze amount of pink duscharge abd that's it... Usually I bleed really heavy for 4-5 days.. But I'm only spotting... I've taken tests and negative- last test was yesterday. Im at the end if my fifth pack btw.