Without seeing it happening it's impossible to say exactly where the problem is, but it is a serious issue that needs to be addressed. There must be a loose connection somewhere. I would have a qualified electrician make a through examination ASAP to rule out the probability of fault on your end,then go after the power company.

2 things to check ... 1st can be done by you if your semi experienced in electrical boxes as well as safety when you open the main panel box up. The Square D QO series box that I had installed had a manufacturers defect in the ground/common bar mounting. Verify that all the mounting screws for the bars are secured tightly an have not been stripped during manufacturing such as mine was. It took 2 electrician visits to finally discover the source of my flickering lights such as you have had. While this might not be the source of your problems it is a good place to start. An remember when you go into the box USE CAUTION since you will be going into a live box but that can be fixed if you by shuting off the main house breaker prior to doing any work &/or verification there. An now the 2nd which will have to be done by your local power company an that is to report it as a flickering light issue to them an they will have a technician send out to verify that all there connections are secure both in the meter panel as well as on their pole (or underground)connections. Squirls do love to chew on the overhead wires an many have done just that. Both of the items that you turned on are a heavy draw on the lines an they may have chewed thru the wires to the point that a phase may need replacing. Their safety for you and their personal is important to them as well. Now these might not solve your problems but it was the 2 things that I did to get my problem resolved. But remember that no matter what you do it's safety 1st no matter what an if you don't feel confortable doing the box inspection than definately get an electrican to verify it for you. Good luck though.