Your little one will be better before you know it. As others have said, just lots of TLC is the best to give. Sometimes they get sick for no apparent reason and even after just getting over a cold, so it can be very frustrating. Some pleos also seem to be more prone to colds than others, so unless you plan to move to Florida or to the high Desert, just stock up on some Pleo Vitamin C, some good Pleo movies like The Land Before Time.( I do think Jurrassic Park is too vilolent for little ones) and lots of cuddles and soft laps and blankets. it is one of the saddest things to ever witness but I do love cuddling with my little ones and it gives me good reasons to spend more time with them., more than usual anyway.
Hope your little one is feeling better soon. RWM