Wow close call

[Bradyloach]

So today I almost killed my bearded dragon. At night the only heat source she has is a heating pad, and something went wrong with that, the night temp is usually 74 but it went down to 64. I picked her up today and bam she was ice ice cold. So I grabbed her and went outside its really hot here. I put her in the sun on me without a shirt so she can get the heat from the sun and my body heat, she warmed up and is back to normal eating lots lots again. So I wanted to ask you guys, I want to make sure that this never ever happens again. I will go to petsmart right now I just want to know, a ceramic heating bulb with no light at all: should I go 75 watt? She's inn a 40'gallon tank. And the basking bulb is 150 watt but I'm lowering it to 75 watt on the cool side and 75 ceramic heater on the cool side?! Any tips would be appreciated thanks <3 please no critizing I think my heating pad broke I already feel so bad