You are 2018 applicant, you should fine out why medical was not done for so long, maybe your file got misplaced. My husband is Guyanese too, 2019 we are waiting for interview, files got transfer to Trinidad.
I am one of three ladies that sponsor our husbands from Guyana we are still waiting for interviews dates as well, the last time I received an email from POS, they were no travels from Guyana to Trinidad, as of this date flights are resuming are also waiting. Hopefully we can get good news next...