I was fortunate. I never went on bed rest or had any formal restrictions, though sometimes my frequent appointments felt like a restriction! Sure enough I did slow down. I continued to work to the very end, but pretty much went to bed as soon as I got home. I also began to park in a reserved spot very near my building at work, rather than the lot a block away because I'd be winded, in need of a nap and having back pain before I sent
Just prior to 32 weeks I asked my OB about this and couldn't believe how easy it was. I wish I had swallowed my pride and asked sooner. Their office submitted all the paperwork and in less than a week the tags were mailed to my door. This allowed me to continue to go to my kids' track meets without using up all my energy on the walk from the far side of the parking lot. It allowed me to continue with some sense of normalcy which was really important to me for the big kids.
I'm sure the process is a little different state to state, but I urge you to look into it. I didn't want to be thought of as handicapped but I also didn't want to be under house arrest. The temporary handicap pass gave me some freedom to get out and about in my final weeks of this triplet pregnancy.