The strangest symptom I had during my third trimester was seeing white stars. There were two instances where I wasn't able to see for a few minutes. It was incredibly unnerving, but everything was fine. The doctor said it was just one of those weird, normal things. Pregnancy is something else!
And, naturally, the best part of the third trimester was feeling this sweet girl roll, move and kick around — even when it meant getting jabbed in the ribs!
Other third trimester symptoms included: leaking breasts, seeing stars, fatigue, headaches, nausea, insomnia, dizziness, rapid heart rate (related to dehydration), more belly stretch marks, occasional swelling (though I think that's more related to the heat), back ache (once or twice), feeling baby and change in movements towards the end.