Use of emergency pill is better reserved for real emergencies which should not exceed more than a couple of times a year. As the pill contains high doses of hormone, you have got a breakthrough bleeding
soon after its use. For the same reason, you may have missed your next period. The symptoms you are experiencing could be premenstrual. If you are due for your next period as you said, it would be polymenorrhoea. See your doctor if you do not get your cycle yet. Wish you good health.