Welcome to HealthcareMagic forum.
Yes, morning after pill can cause hormonal
changes that are responsible for few symptoms such as delayed period, heavy flow and abdominal cramps. These changes usually get rectified in the next cycle.
It is possible you could be ovulating early which can be confirmed by examining cervical secretion, recording basal body temperature
and so on. A more positive way of confirming would be by getting a simple test using ovulation kit. This test is similar to the urine pregnancy
test and can be performed at home. The kit is available over the counter at some location or can be bought online.
Hope this information is useful.
Wish you good luck.