I've had my ball python for 2 and a half years and he is 11 years old. He has always been the sweetest snake and I've never had any problems with him, then a few months ago he got very aggressive and would strike at me whenever I opened the tank. He also was not pooping, so I figured he was constipated. After a lot of research, I figured out it was too cold because the temperature changed outside (it was winter). So I got him a red heat lamp and he was all good. Then suddenly he stopped eating. He didn't eat for 5 months. Finally, about 3 weeks ago, I got him to eat again. A week after his feeding, he escaped his tank and was gone for 3 days. When I found him, he ate but now, he is very aggressive again. He is eating and pooping regularly and the temps and humidity in his tank are spot on. I even downsized him to a smaller tank (40 gallons) to reduce the stress of a large, open tank, like the 75 gallon he was in before.

Is there anything I might be missing, that will help him be happier? He gets all tense and in 'strike-mode' every time I come near his enclosure. I appreciate any help!! Thanks!
-Alyssa