I do not think protein overloading is the problem. I use 50 ug protein per lane, I got a thick band on Western, but the bands are not touching each other. Did you prepare the gel one day ahead? Perhaps the "ears" (the small piece of gel separating the wells) of your gel have dried and allow the samples leak into the neighboring lanes.
Not affiliated with any company. Mention of a specifc product does not imply my endorsement of the product. No conflict of interest or guarantee to work on the advice given. Do as I say, not as I do. Not liable to the loss of your valuable samples.