You might ask your doctor or an OT, they would probably know, but I have never seen weighted blankets, or any other physical therapy tool for that matter, in ordinary stores. I wound up having to make mine too, using the video aspigirlus put up as a matter of fact. I used sand because I didn't have any other filling, it's five pounds and took about three days. Sewing around the sand in the pockets was a little tricky, but I managed it quite successfully in the end. Frankly I'm rather annoyed that PT tools should be so expensive, it feels like they're taking monetary advantage of our different sensory needs.
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"Survival is insufficient" - Seven of Nine
Diagnosed with ASD level 1 on the 10th of April, 2014
Rediagnosed with ASD level 2 on the 4th of May, 2019
Thanks to Olympiadis for my fantastic avatar!