Bitdefender is slowing down my PC. What do you recommend?

I have been using Bitdefender Total Security for years. In the last one-two months? I discovered a terrible slowdown in my PC, when connected to Internet. I recently discovered that's mainly because of Bitdefender. I use my PC mainly for office-related jobs. The due day of Bitdefender is coming in a couple of months, I may think of getting another antivirus software. What do you recommend?