You said you are way too fat...does this mean you want to lose bodyfat? if so, you cannot expect to put on size as well. You have to choose to do one or the other...if you want to get bigger and stronger, eat more...if you want to get smaller (less BF) and weaker, eat less than 3,000 cals. It is basically that simple, although the law of thermodynamics does not always hold true.
To get bigger, 3,000 cals worth of chicken breast and greens isn't gonna cut it. You need to eat more calorie dense foods like peanut butter and weight gain shakes, and you will easily double your calorie intake. If you want to lose BF, chicken breast and greens is fine, but try 2,000-2,500 cals instead and adjust if necessary.
Also, your numbers are killing me. 405 for 5x5 but only 445 max??? 285 for 5x5 but only 315 max??? It seems to be you have a lot of strength endurance, but your ability to produce Fmax (maximal force) is low. This is a strength deficit that needs to be addressed if you wish to increase how much you can lift for a 1RM. Maybe you should try 3x3 for a while and see how that works. Your continued use of 5x5 will continue to improve what you are good at, namely strength endurance, but will have less of an impact on your maximal strength. 3x3 (not Korte, but the Starr/JS routine with less reps and more weight) will allow you to work closer to maximal weight, and get you used to the heavy weight. A good friend of mine can squat 10x10 with 225 but max only about 335...kind of the same as you but a more extreme example.
I hope this helped a little...feel free to ask more as there is good advice to be found here.
