I would possibly add in some shorter sprint work/ plyos on the days that you go to the gym instead of going for a longer run. These will be complementary to your gym work.
I think Saturday's session with the special endurance is good, try some sessions like 2x300m or 3×250 as you get closer to competition. Not so sure about thursday's session of 10×300 bit too much volume for this time of season for my liking.
Also seeing as your 15 i might drop the 3rd gym session and do some form of core stability / extensive med ball. anyway, just my thoughts.
I agree with G Force. Sounds like you're in-season or almost in-season, so I would not opt for the longer runs for aerobic capacity at this point. Speed work is lacking, so at least one, maybe two days of Max V work. The 10 x 300 sounds like extensive tempo, but it's coming after a day off from running, and the volume is high, so not sure aobut that day.
Probably focus on the Max V work a couple of times per week, 800m or less, and keep the Special Endurance runs except on weeks where you have races…the races will serve as Special Endurance. Maybe on weight days add in some extensive tempo if you need it for recovery, but perhaps keep the volume a little lower than the 3000m.