Concern of Dark Energy and the Fate of the Universe

Hello, my name is Verideth, an aspiring physicist. Recently, I read a few physics books, and an idea popped in my head, about the possibility of Dark Energy and two outcomes of the Universe, one idea, is a less respected one, based upon my studies, while the other one supports many theories (Big Bang Theory, Big Crunch, etc.)

My idea took its basis on the conservation of energy. I haven't read much, but Dark Energy is an energy, and can therefore be associated with the law of conservation of energy (assuming no relativistic rules are at play). This is where my idea started too come in, if we were too have the Universe expand to a massive rate, I'm talking billions, maybe trillions, possibly more years in the future, couldn't there be a point where the Dark Energy that is conserved couldn't "support" the expansion? Causing one of two thought up possibilities, a Big Crunch esque fate. The Universe decelrates at a rate, and when the Universe finally reaches sub-atomic level, we get a Big Bang, the Universe goes in to the infinite loop, and yers, if you were thinking outside the box, this means the Universe has a constant set age, each, and every lifetime ;)

Second idea, this one is a bit messy, but it still popped in my head. In short, I call it the space-time freeze, and no, not because of cold weather :). Think of a wave, and that waves trough and peak gets infinitely closer to one another as it progresses through time, causing the Universe to be in an infinitely smaller limit of expansion, going back and forth, each time the difference between is smaller, until it reaches a point where its pretty much zero. Whats this mean? Well, it means that due to the Universe decelerating and then accelerating, over and over again, space-time would ripple, because well, the Universe isn't expanding anymore.

That is my idea, feedback on the idea would be much appreciated.

Thanks! Adios! :-)