Mothers intuition! Lol sometimes they're so fussy and you don't know why and then all tooth springs up 😅 after the first few teeth you'll know when it's happening! Buy some Camilla. It's a homeopathic medicine for teething pain sold at drugstores. Its very gentle, less than tylenol or motrin so I didn't feel as bad giving it. Give it and see if baby's demeanor gets better!
This really sounds like teething. Try just rubbing your finger over her gums. It can help with the pain. You can also look and see if her gums are white. Typically they get the bottom front two first. So everywhere except right there should be pink especially if they’re about to pop through
This is typically when teething pain starts I think. You can try some teething remedies and see if that helps. My baby likes when I massage her gums with my finger (she's almost 6 months). The drooling and chewing on everything can definitely be a teething thing, but can also just be her exploring things and her salivary glands developing.