What I started doing with my 3 month old to get him more used to handling is to handle him for about 10 minutes at a time. I would take him with me when I would prepare his food, then feed him and take him out about an hour later for a
bath. During his
bath I would keep my finger in the water so that he got used to having me as a safe place. I would then leave him in his tank for a few hours until I noticed he started getting sleepy and I would take him out and let him sit on me (staying completely still so he wasn't startled) and he would eventually relax. I know it seems like a lot of work, but it has helped him get used to me handling him!
Also, whenever I handle him it is usually in my room with the door shut so even if he does run, he isn't around my dogs or cat
Hope this helps!