Way too skinny 1.5 year leopard gecko

Question
Hi Tracie!  I am extremely concerned about my 1.5 year old leo.  We have had her since she was a hatchling, her parents both came from a breeder and are very large, healthy leos. She has never been large but now she is losing weight at an alarming rate.  

She eats mostly gut loaded crickets and we have recently began supplementing with mealworms.  She continues to hunt and eat although she is increasingly lethargic in her hunting and she appears to be dragging a foreleg a little bit.  She also continues to shed but not as often as even a few months ago.  

We have her in a 10 gallon tank with an undertank heater and hidey rock and a coconut for a moist area.  Her flooring is reptile carpet.  

Ironically about 6 months ago we had to take her to the vet because she was bloated.  While she was at the vet she urinated an ungodly amount of retained water and that particular problem has not recurred.

Her eyes look clear and she is alert but I am truly frightened by the size of her and I may actually call the vet as soon as I'm done typing this.  Any insight would be GREATLY appreciated!  Thank you so much.

Answer
Hello Becky,

Hm, that is very frustrating.  Definitely get a fecal smear done on her to check for worms or parasites.  Since she is losing weight, then that indicates worms or something else that is competing for nutrition in her.  Her stools, are they loose & smelly, or is she even having stools right now?
What are her temps?  Are you using a basking light in conjunction with the undertank heater too?  
There have been alot of problems lately with leopard geckos.  Cryptosporidium is fairly common in leopard geckos.  
Do you supplement calcium for her?

Tracie