Bleeding after sex is called postcoital bleeding. It might be either because of problems related to vagina or cervix
if your cervix has not been removed during hysterectomy!!
Yes it is essential for u to consult a doctor and get a work up done!!!
In ur case if cervix is removed than most likely cause for ur Bleeding could be from atrophy
of the vaginal and vulvar epithelium (atrophic vaginitis
).Please discuss with your doctor the possibility that this is due to atrophic vaginitis and the medication appropriate for your case.