This sounds just like our cockers first season, I was the same as you wondering if she'd actually had one or not. No blood, even on her bedding, wiped her with tissue several times to check but nothing. The behaviour more than anything gave it away - quite the hussy with any male dog we met! And they reacted to her differently as well, even the neutered ones. She was 10months also and is now nearly 14 months and nothing since, so 99% sure she had a season