[Grammar] was going to /was planning to / planned

[4ania4]

Dear Teachers,

I need to complete the other sentence using the word in brackets. They should both mean the same.

1) I planned to do the shopping but I left my wallet at home. (was)

I ________________________ but I left my wallet at home.

I think the right answer is:

2) I was going to do the shopping but I left my wallet at home.

But I cannot exlude the following one.

3) I was planning to do the shopping but I left my wallet at home.

Do the three sentences mean the same? If there is a difference in meaning, please explain it to me.

Thank you in advance,

4ania4

 

[4ania4]

I have read a bit since I posted my previous message. I think I should have asked if there is any difference between 1) and 3). 2) and 3) probably mean the same.
4ania4