You've expanded very slowly, your had absolutely no damaging turrets defending your rebel colony planet, Heavy Beam turrets are great, but simply cannot down enough targets fast enough, they're for bigger targets, not many smaller ones. Put up some MLRS/Missile turrets, consolidate your fronts, stop spending your money on big things you wont use much (16 beam cannons, with an Ion MKII and an Orbital Mass Driver, WITH a planetary Shield Inhibitor all on one planet, even your home planet, is excessive when you don't have ANY ships, and you're obviously losing on the offensive front.
I agree with LanceFighter, I really don't see how you plan winning here. Your defending too much, and it's in the end crippling your defenses.
Admyae has 0 hostile wormholes, and yet has 15 Basic Turrets, 30 Missile Turrets, 15 MLRS turrets, and 5 Tractor Beams
Wasted energy, wasted ship cap.
Consolidate your resources for the next 90 minutes. Resources includes ship caps, push your fronts up to a more defensible location, don't worry about the rebel colony until you got about 20 minutes left on it, then send in a protection force and setup a command post, don't defend the command post once it's complete, let it fall.
Let yourself actually get ready for this fight.