Yes, it's time to see a specialist -- I would insist on a referral to an allergist; it's lazy of the doctor to say "it's allergies" and not do any further investigation to see WHAT she's allergic to, if that's the cause. It may not be. You need to rule allergies out. Be aware that an allergist will put her through tests for many different allergies and that's not fun but it needs to be done, even if just to rule out allergies as the problem with the eyes. Does she have no other allergy symptoms? Just the eyes alone? That would make me wonder if there is something else going on.
As for the legs: Not sure who the "they say" folks are but often growth means legs hurting overnight; however, for her, the pain may just come when it comes. Again, tell the doctor you want it checked.
Meanwhile, be sure she is hydrated (great suggestion from Mimi) and that means water, not anything sugary and not even juices. And does she eat foods with a lot of potassiium? Bananas, prunes (like candy, truly), dried apricots and other foods contain it - start pushing it hard. Potassium can relieve cramps and if her diet doesn't have enough of it, pushing it could help at least somewhat. Rub her legs when they hurt -- massage them in whatever way gives her the most relief. If she gets "charlie horses" in the calves, have her stand barefoot on a hard, cold floor (not carpet or rug) and flatten her foot against it, pressing her heel hard "into" the floor--she may say at first that it's going to hurt worse but it will indeed help IF she really presses and the floor is hard and cold....at least it always works for us.
Be assertive with your pediatrician. Say you are insisting that it's time to see an allergist about the dark circles -- they do indicate a problem and it's time to find out what it is.