Is it normal to start your period 4 days late then spot a week to a week and a half after your period if your on birth control?

The Birth Control pill can make your period lighter. "A day late" is within the norm for women on or off the pill. If you're expecting that the pill will make your period always come on a Tuesday, four weeks apart, you are likely to be disappointed. For some women the pill makes the period this predictable, but they are the exception.