I replaced my thermostat and now its spraying coolant

Hello, yes, it is likely you have a coolant leak from a hose or pipe or gasket or tube. You'll have to inspect closely to determine physically what the source of the leak is. Keep in mind your 25 year old truck should have had all rubber coolant hoses replaced by now -- probably twice over -- due to age and dry rot.

Inspect closely for cracked thermostat housing !!