I'm sorry, I know this isn't what you want to hear. She doesn't look in foal to me.
Most of the laying down and not wanting you to touch her seems like normal behaviors to me. There's no udder change that I can see. She doesn't seem to have any lopsided belly evident.
If she were mine, I'd go ahead and start conditioning her. In-hand work and light work won't hurt hurt on the *very* slim chance she's in foal. In fact, being in shape will actually help her in the foaling process. It's hard work!
When I worked on a breeding farm (back in the last century!
) all the broodmares were kept in light work during the last 4 months of pregnancy. They were lunged, worked in the round pen, ponied or driven. LOTS of over poles work, so they'd drop their heads and round their backs....lifting and strengthening those belly muscles.
In 3 foaling seasons, with 50+ foals delivered, we only ever lost one foal. Her first time mom got startled by a new farm pup barking at them. Foal was asleep and mom accidentally stepped on her, causing internal injuries from which even surgery couldn't save her.
Those mares had the easiest, quickest deliveries. Even client mares that didn't come to us until 30days before their due dates were hand walked twice a day. No mare was every worked hard enough to breathe very heavily, nor to a hard sweat. A bit damp was acceptable IF they were in winter coat. (We had many Jan/Feb foals in the younger mares. Mares over 15 years usually foaled Aug/Sept timeframe.)
So my point to all this is, keep her on your pregnant mare feed program. Be sure to put your hands on her daily to check her weight, as the winter fluffies can trick the eye. Keep her in light work through the winter, or until you are satisfied as to whether or not she's in foal.
Good luck, and don't let her boss you around. If you want to check the ****ies, she needs to let you do so without trying to take your head off.