Q: keyboard or mouse won't connect?

i just bought my iMac last month, and my keyboard and mouse sometimes won't connect. The lights keep flashing and I've left them searching for the iMac but i spent about an hour letting them "pair" which never happened.  I have to manually reset my iMac to connect them both again. Both battery lives are at 100%. What i think might cause it, but I'm not sure, is that when i go to bed, i turn off my keyboard by pushing the button till its off, and turn my mouse off, and put my computer to sleep, instead of shutting it off. I don't know, does anyone have this issue, or solution?