What happend to my potato plants :(?

I planted some potatoes early this year (like Feb.) and they have gotten really, really tall to the point of falling over. Most have flowered already have healthy foliage and looked to be doing well but when I pulled one up today the potatoes were only the size of a pea! What went wrong? Do you think maybe they needed more time? They are red potatoes and I live in zone 8 in FL.