As other answers have concluded, modal interchange is a great term to describe what's going on here. Between A major and A minor, a majority of the chords can be explained pretty nicely. I do have a few additional thoughts about the progression (mostly in question form, since there's not enough context for me to make the determination myself - however, the principles behind what I'm asking apply to any analyst):
- The second line A C G D is a pattern often referred to as the plagal cascade when it is done in A minor, so perhaps that pattern dictates the perception to some degree.
- The last line C G B7 B7 on its own is reminiscent of E minor, however the progression jumps back up to an A chord to repeat. Is it possible that your progression could be better interpreted as periodically shifting between two (or more) keys?
- The fact that most of the apparently-nonfunctional chord movements occur between 4-measure phrases might also be of relevance. Perhaps this means there's merit to looking at each unit of hypermeter (relax, every phrase of 4 measures) as its own separate thing?
- There are two dominant 7th chords, D7 and B7. Both are immediately followed by the major chord built on their 7th (e.g. D7's 7th is the note C, which is the chord after the D7, and same for B7 and A). Could that parallelism reveal anything about the structure of the music? In fact, similar things can be noted about other mini-sequences: I noticed also that there are three occurrences of a major chord moving downwards by a major third, which is not common in most functional progressions. Do you think this observation has meaning?
Context is everything here. Is there a melody? It may even be best to simply accept that the progression defies functional expectations, and there may be little we can do to map it onto the patterns we commonly observe in functional music. My best advice if you want to understand the progression is to ask yourself why you picked the progression that you wrote. You weren't just randomly throwing chords together, right? You probably liked the sound of the progression, otherwise why isolate those specific chords as worthy of analysis? So try changing things, little things, and see what changes make it sound similar and which make it completely different and wrong. If you can pick out what the important things about the progression are, you can start to understand why you like it and how to (re)create similar things in your compositions.
Here's a head start on some little changes: Strip it down to only the root movement. Do you still like it? If all the A major chords were changed to A minor, does it still sound good to you? What about if some of the major chords become 7th chords? (if you can figure out which 7th chord type to pick that's a clue as to function) Or what if the last B7 chord were an E7 chord? See what changes matter, and which ones don't.