When we first get into a relationship, our brains get flooded with all kinds of wonderful neurochemicals- oxytocin, dopamine, adrenaline. It's like being high all the time, and it doesn't count because it's all natural. So, we float around in a fluffy pink cloud of stupid, and hopefully avoid operating heavy machinery, signing important documents, or making life-altering decisions.
Just breathe and wait for the buzz to wear off, then figure out what to do.