"That" and "this" are demonstratives and so don't have a tense associated. The tense comes only from the verb: Past --> "I'm sorry that happened." --> "I'm sorry this happened to you." Present --> "I'm sorry this is happening." --> "I'm sorry that happens." Future --> "I'm sorry that/this will happen."

They don't refer to time. In the simplest uses, they refer to place. "This" means relatively nearby, "that" means farther away. This restaurant here serves Chinese food. That restaurant across the street serves Mexican food.

Thanks Alec and Dan for your replies.