I changed bc pills i just got off my period and starting my 4th pack but i just started bleeding again is this normal ?

Breakthrough bleed: Breakthrough bleeding (bleeding at the wrong time) is very common on birth control. It happens in about 1/3 of users. Its no big deal and usually self corrects over time. If you are not satisfied or it continues to happen then consider using a different birth control method. It is a common side effect and does not mean something is wrong or that the pill is not working.

Could be: Changing BC, especially if one has a different hormonal concentration, may cause bleeding issues. If you do not regulate on the new pill, see your Dr. Good luck.