I learned the under-exposure lesson the hard way too. (Same for B&W BTW.)
As to the the color shifting, that is to be expected with underexposure.
With color film you are actually dealing with 3 separate exposures; red, green, and blue. Shadows are typically bluish. Even if you, your meter, gets the reds and greens right, if the blues end up way down on the toe of the curve you have a problem with color balance. The raw, uncorrected scans may even show this in a histogram; blues left, reds right.
Much of this is correctable in the enlarger or elsewhere but, just like any other deviation we make in photography, it does require work and adjustments.
Ansel used "Expansion and Contraction", which are the same chemical processes as "push and pull" but his aim was different, he wanted to improve a negative's contrast to make printing easier, he was not trying to push the film so that he could underexpose, i.e. use a faster shutter speed.
The trick to using a push or pull is knowing what is going to happen before hand, an option you did not have with this roll.