Trouble telling if my puppy is in heat

I’ve never had a female dog before and I’m having trouble telling if my dog is in heat. I was expecting it to be much more obvious but I read that it can be pretty subtle. She is licking at her vulva a lot and I think her vulva is a bit swollen but honestly I don’t have a side by side picture I can look at to tell. It’s not red. She’s been getting up during the night and wanting to go outside and stay out there, when she has previously been sleeping through the night. I noticed she’s following me around a bit more than she is with my partner. Today we saw some drops of blood on the floor and on the back of her legs, but when inspecting the rest of her to make sure it wasn’t something else, it looked like I may have cut her quick while clipping her nails. There was no blood initially and she didn’t yelp, and the blood was found over an hour later so I don’t think it was that but I can’t be certain. If she is in heat she is keeping herself very clean. Her spay is booked for January, so if she is in heat I will need to rebook that. Will it become more apparent as time goes on? I don’t want to miss a uti or something because I thought she was licking herself due to heat.