My roommate started a fire in our apartment a couple weeks after we moved in together - this was about about 10 years ago. Sprinklers put the fire right out, but water damage made the unit uninhabitable. Here's some tips from my experience.
Take care of your immediate basic necessities to live. Find a place to stay short term. We stayed with family, so we were not sleeping in cars (illegal in many areas). Crash with friends/family, get a cheap motel, look for emergency community shelter services. Call your local Red Cross. Did you lose any basic necessities, like a change of clothes or food and groceries? They may provide some disaster relief for you. In my case, we lost all groceries in the kitchen and Red Cross gave us a Visa debit card with $250 that could be used at grocery stores only. If we had lost clothes, they would have provided additional funds for basic clothes for two days.
Read your lease - look for any language about rent due while unit is uninhabitable for any reason. My lease had language that released us from being responsible for rent until the unit was repaired and inhabitable. It also had language that would allow us to break the lease if repairs were not completed within a reasonable time frame (30 days). As the landlord believed we were at fault, they tried to tell us rent was due. I sent them a letter citing each provision in the lease and they relented. They even credited rent that had already been paid once we moved back in. They likely won't pay for any replacement housing (read your lease). If you need something more long term that requires a new lease elsewhere, make sure you can opt out of your existing lease so you aren't stuck with two rent payments.
If there is any question of FAULT, you will have some bigger issues. In our case, the fire was caused by unattended cooking on the stove by the roommate. The landlord tried to bully us to pay them for repairs - I told them to file a claim with their insurance (we were students and had no assets). Again, read your lease - in our case there was a joint and severability clause, that means we were all equally on the hook for everything on the lease, including damaged caused by one roommate. A few months later, the insurance company's subrogation department mailed us, demanding payment for the damages ($47k) or they would sue. Subrogation department is a fancy term for "insurance company getting the money they paid out back". We replied that we were students with no assets, and without admitting fault, we could offer them $1500 to settle the matter and avoid costly court expenses. They immediately replied looking for 20k. We went back and forth a couple times until they offered 5k, which we agreed to, with a payment plan over 10 months. You might seek legal advice if you find yourself in our situation.
It was a hassle, but it worked out In the end. I hope this info helps you with you situation.
Ps, and for anyone wondering what happened with that roommate? We worked it out and got married a few years later.