This happened to us in the last housing recession in 1992.
The simplest solution is just find another flat/house to rent and leave ASAP but only as long as you can be sure of getting your deposit back. Write to your landlord / agent and notify them you intend to leave due to repossession and demand the deposit is repaid before you leave.
If you are in financial difficulty and / or cannot afford to rent another flat / house then do wait to be evicted so that the local authority will be forced to rehouse you. Do not make yourself homeless by leaving early.
If you are really stuck and canot afford to move then do go to the hearing and ask if you can speak to the judge or even better just write him/her a letter. They may give you more time before eviction.
Do write to the lender nad offer to pay rent to them if they will sign a new tenancy agreement. They will probably not reply as they will not want to acknowledge your tenancy but if you keep several copies of that letter then do also attach a copy to the letter you send to the judge to show you have tried to offer to pay the rent to the lender and you may get sympathy.
As you are pregnant and have another child you may well also get more sympathy and more time to move.
In reality you have few rights though unless the tenancy was signed before the mortgage was taken out.
It is the most shameful aspect of the current rental market that landlords can just stop paying the mortgage and the tenant suffers. There is so much talk of helping homeowners stay in their homes at the moment due to the recession but no help for innocent tenants.