I think you’re screwed. Go here:
https://www.immd.gov.hk/eng/services/visas/visit-transit/visit-visa-entry-permit.html#notes
You are unfortunately a caret symbol country:
Wikipedia for example summarizes it as:
https://en.wikipedia.org/wiki/Visa_policy_of_Hong_Kong#Visa_required_nationals
Hong Kong does not permit nationals of Bangladesh (and several other countries) to transit without a visa, not even in the international transit area of the airport. If you try to go without one, the airline may deny boarding.
You have two obvious options at this point:
First, you could try to obtain a visit/transit visa from Hong Kong. Their official web site says that this may take up to four weeks. Your Hong Kong visa application must be submitted to the China Visa Application Center which serves your province. It seems unlikely that you will receive this visa before your flight.
Or, you can change your flight itinerary to transit through a different country. Likely you will have to purchase tickets on another airline.
Credit:stackoverflow.com‘