2003 Ford F-150 Engine noise / squeek

Recently had my knock sensor replaced a week and a half ago and everything had been working fine. Was driving around yesterday and turned on my A/C for the first time this year. After about 1 minute of my A/C working I started to hear a slight, rapid, ticking coming from my engine compartment. Then I also realized that when I would accelerate to pass on the interstate it would downshift to accelerate but whenever it would shift back into overdrive it would make a squealing noise identical to what a bad belt sounds like. At first I thought it may have been related to all of the maintenance involved in changing the knock sensor until I realized it coincided with me using the A/C and the squeaky belt sound. I don't know if possibly my A/C compressor is bad or not. Thanks in advance for the help.