Yeah that's kinda just how it goes when you're starting out. Work on learning to use wake-ups to back them off when you are being pressured. I haven't been playing these terribly long in any serious sense (pretty much started with MK9) and am finally starting to get used to things. Online is tough due to input lag as well. But try to not really go for combos to start out, just work on trying to read your opponent, figure out what they are going to do next based on how they've been playing, and see what works best to counter their play. Once you get better at this, THEN start figuring out where/when to work in combos.