Clucky

I have an albino gecko that I purchased from a reptile dealer , ive had her for about 2 months and she is very pickyonly eating like one ckicket every 2 weeks. When i first got she weighed 16 grams she was kept in a 5 gallon with an overhead lamp with the temps at 85-90 degrees, she wasnt eating at first but after a couple of days she was eating ckrickets and mealworms .After a month it put on a couple of grams 18 and i thought she was doing well. Then one weekend she just stopped eating and its been downhill eversince.Im always throwing crickets in the enclosure but it just looks at them and the ckrickets eventually die. I got her to take a crickert the other day but nothing since.I have now changed her to a heated rack were the temps are 85-89 degrees.Im just a little worried that this girl isnt going to gain any weight, any advice on what to do.