Another single bought when it came out and meaningful for this listener as it was cited by Lennon in the 'lover's spat' phase of their friendship when John referred to the single "Since your gone you're just Another Day' which frankly shows John's crassness and hits at what he always took to be Paul's sentiment at the expense of the hard rocking Johnny and only respond this conflict later on  . . . . . me I was on Paulie's side in all this and it is as haunting a song as Macca has ever written . . . . . . as an aside - my favourite quote from the period is when John accused Paul and Linda in the same song 'How Do You Sleep?' of 'living with straights' an accusation of not being hip enough to be cool and smoke heroin like him n Yoko, Paul replied "Of course I live with straights, my children are straight!' Ouch gotta burn! 
Fortunately they made up later  . . . . . . . . 

On this day in music history: February 19, 1971 - “Another Day” by Paul McCartney is released. Written and produced by Paul McCartney, it is the first post-Beatles solo single for McCartney. It is written as a “thematic sequel” to “Eleanor Rigby”, describing a woman as she struggles to make it through the “drudgery and sadness” of her daily life. Recorded at A&R Studios in New York City in December 1970, it is cut during the sessions for his forthcoming second solo album “RAM”. Backed with the mid tempo rocker “Oh Woman, Oh Why”, the two tracks are released as a stand alone single. Picked for release by engineer Dixon Van Winkle, it is quickly mixed with acetates sent to one hundred radio stations who begin airing it immediately. The mono mix sent to AM radio stations features heavy compression with an elevated amount of bass, that is not present on commercially issued copies which are issued in stereo only in the US. “Another Day” peaks at #5 on the Billboard Hot 100 on April 17, 1971. Later in the year, John Lennon makes reference to “Another Day” in his song “How Do You Sleep?” (from the “Imagine” album), with him taking a swipe at his former Beatle band mate, with the lyric “The only thing you done was Yesterday, and since you’ve gone you’re just Another Day”. The song is his response to McCartney after he believes that the songs “Too Many People”, “3 Legs” and “Dear Boy” (on “RAM”) are critical of him. “Another Day” is not issued on an album until 1977 when it is included on the compilation “Wings Greatest”. “Another Day/Oh Woman Oh Why” is reissued in as a limited edition 7" single (packaged with a replica of the original Norwegian picture sleeve) for Record Store Day in April of 2012, and as bonus tracks on the CD reissues of “RAM”.

thanks to the most excellent Jeff Harris' blog 'Behind The Grooves