Bigger Tank/Brumation/Illness?

[cron14]

Hi all! My beardie has been acting very strange lately and I'm having trouble figuring out what it is. I have seen the uptick in brumation posts but Little Foot has some other things going on as well. I live in NYC and the temperature this time last week was 85 degrees F and now it is dropping into the high 30s. Long story short, Little Foot's behavior has totally changed seemingly overnight. The past few days he's been sleeping on and off throughout the day, spends the majority of his time (from what I can see) glass surfing while he's awake and has not been eating nearly as much as he used to. He has also defecated 2/3 of the last days (much less than normal but that could be due to lack of food). I have had him since May and have never experienced these issues before. He was also shedding what seemed to be constantly and that has gone away. I have him in a 36x18x16 roughly with a CHE and a UV (3 months old) basking lamp as well. When I got little foot from petsmart he was roughly 5g and maybe 4-5 inches.(I do not know his age) My last measurements was taken Sept. 30th and he was 240g and between 13-14 inches. I can't figure out if its time for a bigger tank, brumation or illness. Please help Im worried about the little guy.

 

[Gormagon]

What are your Temps in his basking spot, warm end and, cool end?
What type of uvb bulb are you using?

 

[cron14]

Exoterra solar glo 125 watt and they're usually between 105-110 but I will admit since its gotten colder I have not gotten a read on them. The last week has been extremely busy for me so I usually only had enough time for feeding/cleaning and some handling. I switched to using a reptihammock as a basking spot a few months ago but I am thinking of building a tile platform to hold heat better. Before I did that I wasn't sure if I should upgrade to a 55 gallon breeder. His colors have been as bright as they've ever been with only a few times of being dark in the cage. Cold end is usually between 75-80 warm end closer to 85. Using a probe thermometer. Again I will admit, I was not monitoring that closely the last week and since you brought that up I'm thinking temperature could definitely be an issue.