Took dulcolax for constipation last night,now have severe diarrhoea and stomach cramps..is this normal?

i took two 5ml spoons of dulcolax liquid and 4 dulcolax perles as i don't find them effective enough separately.could this combination have given me the diarrhoea? I now have lower abdominal cramps and the urge to have a bowel movement but nothing happens..:/