Trackpad jumps/skips on it's own

I know this has been answered a few times in different ways but still wanted to tell you all my problem and see your advice... Since I got my phone, which was back in Feb, I've had issues with trackpad sensitivity. I have it set on 50/50 actually and it still happens... It's when I'm typing a text or message on Facebook... With Facebook, it jumps so much that I either end up hitting "Send" before I'm ready or it jumps downward and clicks on the person's profile pic taking me to their profile, regardless of where it takes me, it's annoying bc then I lost the entire email and have to start over. If I don't type the message slowly and keep my eye on the screen then I lose it. Also when typing in Facebook as well as text messages, it doubles letters quite often, like if I hit the "Y" key it'll get "yyy" alot. As well as it turning certain letters into symbols when I didn't ask it to. I considered getting a brand new phone back in Feb when I first bought it, but I had read a lot of other people had problems, some worse than mine, and worried if I got a different one it would end up being a worse off issue. It mostly seems to happen when I'm in the dark, like laying in bed at night or in the car at night, but it also has happened at all times of the day and all locations. Any insight from anyone that may have had this issue... Any fixes or should I just learn to live with it as I have been (even though its super annoying)
Thanks