I would try to renegotiate unless you want to take the big investment of doing your own place. Plan on working a lot harder on the business die of it and it may take away from your training.
Your monthly rent for 1,300 sq feet would be from $15 sq foot (very cheap)to $30 sq foot. $1625 monthly to $3250. Don’t forget the triple net (taxes). that can range anywhere from $5 to $7 per square foot. Your rent just went up with taxes to $2166 to $3791 (hoping your taxes are at $5 sq foot-I pay $6.50 sq foot for taxes). Electric, phone, water, gas and other possible things like leases for equipment (TV, counter, office supplies, phone, printer, training equipment, etc…
If you got another trainer with good amount of clients to split cost, I would consider it. Make sure you do a contract with commitment from other trainer if you get that far. Now you are becoming a business person that is also doing training. I think it is worth it for some depending on your overall direction for your career.