Stuck paying rent for two apartments

To summarize at the start.

I'm in Quebec, Canada. We have a special court for landlord/tenant disputes called 'The Regie du logement' that we deal with before normal court.

Landlord told me I could move out early after months of discussion. I (lease holder on apartment) informed the roommate (Not on the lease) months in advance.

Roommate refused to move out, is unemployed and squatting in the apartment.

Landlord is now suing me for 'lost income' at an inflated rate over the previous rent amount I paid when living there, including cashing post dated cheques he had held onto AFTER I had moved out.

I spoke to the landlord's lawyer and they said that it might take multiple months for an eviction on the previous roommate to go through and I'm stuck on the hook for rent for that entire time.

I'm stuck now paying rent on my new apartment, as well as every month having more 'debt' build up until the court case goes in front of a judge. I've been told that I will have to pay up front most likely and then follow up with a lawsuit against the occupant roommate to get him to repay me for the lost rent (when he gets a job eventually, if ever).

If anyone can even spare a few dollars it would be greatly appreciated.