They can have phantom pregnancies. Although it might in theory be the wrong time of year, in practice this time of the year is common for cloudbursts (the phantom kidding of a phantom pregnancy). When did she last come in season? My running through girl came in season regularly from October until February, so 5 months from February is July! She is enormous too, so I am not sure if she is having a phantom pregnancy or not. Generally when it's a phantom, it is just excess water they fill up with.
Beth