pills can cause side effects like breakthrough bleeding
, dark brown discharge, bloating sensation and pain abdomen etc,
so your symptoms may be side effects of pills,
but as the pills are having around 1% failure rate if you had intercourse around the middle of the cycle or if you missed any dose of pill, once check for pregnancy
by urine or blood test
if comes negative, you can wait as these symptoms will subside soon, if not better to consult your doctor once to find out the cause and if needed change the type of pill.