I was working (past continuous) and I worked (past simple 1)

To talk about a temporary situation that existed at or around a particular time in the past, we use the past continuous:

When the delivery man arrived, I was watching TV. 

My head was aching again, so I went home. 

Compare the use of the past continuous and the past simple in these sentences:

She was running as she left the hotel.

When she realized I was looking at him, he turned away.

Tom dropped his wallet while he was getting into his car. 

We often use the past simple to talk about a completed past event and the past continuous to describe the situation that existed at the time. The completed event might have interrupted the situation, or just occurred while the situation or event was in progress.

We don't normally use the past continuous with certain verbs describing states:

This house belonged to the state (not ...was belonging to...)

When we talk about two past actions or events that went on over the same period of time, we can often use the past continuous for both:

My friends were baking some cookies while I was cooking some pasta. 

My cousin was drinking beer while I was frying some chicken. 

However, we can often use the past simple to express a similar meaning: • Mario worked in a restaurant while he lived in London, (or ...was living in London.)

When we talk about two or more past completed events that follow each other, we use the past simple for both. The first may have caused the second:

She got up when the alarm clock went off.

He jumped out of bed and ran to see who the parcel was for.

When we talk about a permanent or long-term situation that existed in the past, we use the past simple rather than the past continuous:

When I was a child I played basketball, (not ...I was playing...) 

However, if the situation was temporary, we can also use the past continuous. 

Compare:

I was working in a bank during the spring of 2002. (or I worked...) 

He worked hard all his life, (not He was working...)