This could quite possibly not be the case, but I just went through this myself. My situation left my overdrive/distortion pedal way quieter than everything else. I found the cause to be a lack of power. I have a lot of my pedals hooked up to a power supply and I’ve found that some effects such as reverb and delay do alright with lacking power but overdrive really needs all of the voltage it can get. By that I mean all it needs.

In other words, check out the power it’s receiving. Also, I know its just personal preference but I would put my overdrive/distortion pedals earlier in your chain, like before modulation stages. Just a thought. Hope I could help!