Might be, if you were not adapted to it. The best advice I've seen on breathup is to forget about your breathing, let your body take care of it. IMHO you can follow that with a small number of purge breaths, but you don't have to and it is less safe. That works for most people, but you have to find what works for you.
What I do is a little different. I spent so many years breathing deep and slow that my subconscious will breath deep and slow in the water if I don't think about it. I consciously breath very shallow, right on the edge of feeling the need to breath. . Breathing gets slower and shallower(less than a 5th of a lungful) as I get near ready, then a couple of diaphragm only purge breaths and go. Works for me, might not for you.
I went to FRC (half lung) diving a few years ago and finally took the advice of better divers and stopped overbreathing. Takes a while, but you get used to the different c02 level and pretty soon your dive times are back up. That, combined with a better dive response from less inhale and more c02 and my dive times are much longer than they used to be.
Connor