why os my wifi slow now?

[AC Question]

Ok i have a lg2stylus from staoght talk my wifi is usally really fast but after a little over a month my wifi on my phone is slow but everyone eles phone is still fast. Ive tried putting a virus scanner amd a boost app on and its still pretty slow. Idk what I've done but this happen to my last phone after a month or so but i had to replace that one because of a broke screen. So idk how to fix it. I love this phone and i really wamt this problem fix someone pls help me!