Lump on my ferret’s neck, unsure what to do

Before I start, I have an appointment for Thursday at the vet, but I am unsure if I should take her to an emergency vet now. Last night I found a lump on my ferret’s neck (she’s about 3 years old), under and to the left of her ear (so less near the front of the neck). It’s moves with the skin a lot and doesn’t seem to hurt her or bug her at all. She does itch quite a bit in that area when waking up but I am unsure if it’s to get to her ear or the lump. It’s the same color as her skin as far as I can tell, it seems to be fully under the skin and fur.

I checked the rest of her and there’s no other lumps, but I read that fatty underarms could be a bad sign and I felt her and it’s seems there’s a little fatty “pack” under each arm but not swollen or anything, they’re each very little so I’m not sure if that is normal for ferrets to have with their anatomy or not.

She is 100% herself other than that lump on her. At times she has had “seedy” poop but we switched her food and she seems better with that now. She is quite little but has appeared to gain a tiny bit of weight recently, not too much because she has just always been small. When she plays she doesn’t seem as energetic as other ferrets I’ve seen but she had always been this way, and can still spend hours walking and trotting around the house chasing everyone around and playing. She just doesn’t make much sounds to show excitedness but again she has been that way a very long time.

Should I take her to an emergency vet? Or should I wait for Thursday? I am scared of lymphoma.