I’m sorry to hear this.
On their own, what you are describing are not specific symptoms of any illness which a vet could necessarily use to diagnose anything. Piggies do rumble (sows do it when in season - you don’t say how old she is, she could just be experiencing a strong season and making her more hormonal), not popcorning isn’t a specific symptom of anything.
But you know her best and can tell if she is not herself. A change in behaviour can sometimes be a sign they are feeling unwell.
At this stage and the fact that she is not displaying any specific symptoms of illness, our advice would be to switch to daily weight checks so you can more closely monitor her hay intake. If she is unwell then she may well not eat enough and could lose weight. Be prepared to step in with syringe feeding.
If, however, she be lethargic, stops eating, stops moving etc then she would need to see a vet straight away.
https://www.theguineapigforum.co.uk/threads/weight-monitoring-and-management.171577/