Pain after running

I don’t know maybe someone can give me advice.
I’ve started running on my treadmill again the past two weeks and I have not missed one day of running. In fact sometimes I run up to three times a day.
But suddenly I am in agonizing pain in one of my knees, and I can’t walk very well And I guess I’m wondering if it sounds like a torn muscle or what else it could be.
I’m hoping not to have to go to a doctor just because I’m so tired of having to wait like 6 to 8 hours just to get seen.
The pain is really bad and I’m also on naltrexone so getting prescribed like pain meds would be a big pain in the ass because naltrexone makes it to where I can’t feel opioids.
And I’m on it because of my alcohol addiction.
It’s sort of near the top left inner side of my knee (on the right side of my left knee) like right on the side of the kneecap
It is very agonizing
I had felt pain in my knee, but it wasn’t that severe and then I ignored it and decided to run yesterday and now I am an extreme pain