I have a couple of things to let you all know about.
Please look what your sheets are made out of.
I found a variety of sheet materials and qualities.
1) Extra soft flannel-like material (100% polyester - synthetic material)
How is polyester made? (you won't want to use it after you know)
2) Real flannel should be 100% cotton or wool
Flannel is a soft woven fabric, of various fineness. Flannel was originally made from carded wool or worsted yarn, but is now often made from either wool, cotton, or synthetic fibre. Flannel may be brushed to create extra softness or remain unbrushed. The brushing process is a mechanical process where a fine metal brush rubs the fabric to create fine fibers from the loosely spun yarns. Typically, flannel has either a single- or double-sided nap. Double-napped flannel refers to a fabric that has been brushed on both sides. If the flannel is not napped, it gains its softness through the loosely spun yarn in its woven form. Flannel is commonly used to make plaid clothing, blankets, bed sheets, and sleepwear.
3) 60% cotton - 40% polyester blend sheets (still not acceptable)
4) 100% cotton (watch out for regular cotton - cotton is the world's most pesticide sprayed crop - click below for more info)
5) 100% organic cotton - you can find organic cotton sheets at Walmart and other inexpensive stores
For your health pick the best bedding to sleep on. Walmart also has some organic cotton clothes as well! When you see the organic label you can be sure that the cotton was raised without harsh and synthetic pesticides.