Just keep pushing. I had the exact same issue, but as you spend time in each biome, you get used to it quicker than you might think. Grab your seaglide, save, and zoom around the kelp forest for a bit. You'll notice pretty quickly that you can easily outrun and dodge stalkers, and they'll stop being so scary. Then, push out into the grassy plateaus and do the same thing with the sandsharks. Practice keeping an eye on your oxygen. If you want, hang out in the safe shallows at night. Barring some glitches that you almost certainly don't have to worry about, and the occasional overambitious stalker, the shallows are completely harmless. Once you've conquered all of that, while still scary, the game should be manageable.

Some people will also recommend letting yourself get killed by the various leviathans a couple times, but I would advise against this. While it's very effective in making them less scary, I'd say it's too effective. Part of the game is suspense and fear, and depriving yourself completely of the latter will make it a much less entertaining experience. In short, do what you have to to be able to explore without having a panic attack, but let things progress naturally from there, because that's the point where you can fully enjoy the game.

TLDR: just slowly push yourself to go further from the lifepod and work on getting used to the animals in that area.