>>apparently it looks like it needs water to swim in which I don't have a tank for.
You don't need a "tank!" A large "rubbermaid" (any brand of appropriate size---bigger is better) tub makes a great habitat! A plastic (never used) paint-roller pan can provide a depth of water with easy access; easily cleaned, get two so one can be disinfected while the other is in use. Change water daily with tepid water; treat water or let stand for 24 hr if chlorinated.
>>a heat lamp, some shrubery, pellet flooring and a water dish
Is the "heat lamp" thermostatically controlled? Provide a gradient of temperatures (72-85F), at least a couple of thermometers to ensure proper temperature.
"Pellet flooring?" Not usually appropriate---can dehydrate the turtle and can become moldy quickly (but the pet store $ells it); moist sphagnum moss (unmilled) is good.
UVA/B lamp may also be needed; will your turtle be directly exposed to unfiltered (no glass, no plastic) sunlight several hours per day?
Offer a varied diet! Earthworms (bait store), green leafy veggies, tomatoes, over-ripe fruit, moist Tetra Reptomin sticks.
>My first suggestion is to take your animal to a qualified turtle veterinarian.
NOTE: "qualified!!!" This means if your vet comes up with a quick diagnosis of vitamin A deficiency, !!beware the vet!! Not all vets have experience with turtles. Soak your turtle in warm water; this not only helps to hydrate the turtle but may stimulate defecation! Save any "poop" for the vet so that s/he'll be able to do a fecal---very important especially if this is a wild-caught turtle.
Do not hesitate to ask more questions!!!!!!!!!!! These are great personable turtles given a chance!