If you call 999 now, they try their best to avoid sending an ambulance. I've only ever called once cos there was someone collapsed on the pavement, I couldn't wake her and she didn't look like they were breathing, even when I put my ear as close as I felt comfortable to my mouth it didn't seem like she was. The operators then got me to put my ear right to her mouth and she woke up, but I'd been explaining for at least a minute that I didn't think she was breathing before then, that her chest wasn't moving, I couldn't wake her, etc. She was out of her gourd and claimed to be fine so I left her to it, but I was really shocked. Like if she'd actually not being breathing, the time they spent arsing around would be more time her brain was starved of oxygen.
Don't bother with 999 unless you've just witnessed a major car accident or something, 111 is pretty good and can save the hassle of going to the doctor unless you actually need to.