Thanks for writing in.
Even though you are not having abdominal pain
and have little cramps; you have vaginal bleeding.
So we need to rule out cause for vaginal bleeding [as you are due for your periods next month 5th].
I would suggest you to get ultrasound
-pelvis abdomen done to find out causes for vaginal bleeding. It is less likely that your implant getting misplaced by the hit of ocean wave.
Wishing you great health.