I have read you query in detail. In my opinion you must go to ER and get your X-ray and Sonography
X-ray to rule out any minor fracture
of the pelvic bone.
Sonography for any collection of blood and fluid in pelvic region. As you have cold
, swelling and loss of appetite, there may be a chance of hematoma
in pelvic region.
Its better to diagnose it earlier and get started with the treatment.
Please go to ER and consult a doctor and go through the investigation.
Best Wishes and have a speedy recovery.