Most of what we refer to as “conscious memory” are episodic and semantic memories. Episodic memories tend to be autobiographical (“It’s all about me”), while semantic memories are more about learned information (“Just the facts”):
Episodic and semantic memories are created through a process known as encoding and consolidation. (See this article for more detail on memory encoding.)
Retrieval of episodic memories tend to be an “on the fly” reconstruction of memory traces that approximate the original memory formation. “Flashbulb memories” are distinctly vivid, long-lasting episodic memories with a strong emotional component — where you were on 9/11/2001 (or other personally important date) is an example of a flashbulb memory.
When people become concerned about “short term memory loss”, they are typically referring to real or perceived impairments in the ability to form new episodic and semantic memories, or recall fairly recent episodic or semantic memories.