Electrical nightmare
Contact your power company Right Now and report an outage

It'll be fixed for free in 2 hours. 

You actually have a power outage.   Your house is partially working because electricity is delivered in 3 wires.  When one wire fails, there's a 2/3 chance of having your 240V circuits go out along with half your 120V circuits (unless you turn on a 240V appliance, then weird things happen).  

However there's a 1/3 chance of the 240V appliances continuing to work, but the two banks of 120V appliances drifting significantly off 120V.  One goes higher than 120V, and the other one goes lower by equal amount.  They still add up to 240V, but one appliance is getting 190V while the other one is getting 50V. And worse, it changes as you turn loads on and off.  This is called a lost neutral. The neutral's job is to clamp voltage at 120V.  

This last mode is the most dangerous and the most difficult to detect. This is usually on the power company's end.  Given that you just replaced everything on this end, I'd say 99% in this case.  The power company fixes this for free.