I assume that you have asked for the temperature to be turned down? If not, you can do so.
It is quite difficult for your crew to assess cabin temperature. When in the cabin, they tend to be both standing and active: Crew perception of temperature will always be different to that of somebody sitting still. When crew are in the galley during non-service periods, they are still (usually) standing, and are adjacent to a chiller system and the doors - both are sources of low temperatures.
There are many sophisticated bits of technology on an aircraft - cabin heating systems seem to be the forgotten child. In approaching 35 years of flying for a living, I have never worked on an aircraft with a truly effective heating system.
Cabin temperature is inevitably a compromise for a large group of people, some of whom travel in T-Shirts, some in sweaters. During sleep periods, people, as a general rule, tend to feel colder.
Shortly, one of the forum cynics will tell you that the temperature is always deliberately turned up by the crew in order to keep passengers drowsy and therefore quiet. This is occasionally the case, but never as frequently as the legend would have it: An inappropriate temperature generates more complaints (i.e. work) than getting it about right.