It sounds like cystitis, doesn't it?
She's 15 and a half (with only 3 grey hairs on her, bless her) and has always been a bit skittish and antisocial. More so these days though, and prone to calling mournfully around the house and unable to settle.
She must have the urge to wee really frequently as she was only in the house for about 1 minute and she headed for a pile of newspapers in the lounge (litter tray was out). She only managed a few drops, and they were red
.
Then I saw her outside in her litter tray, and she was squatting for ages. Poor thing hardly managed a drop.
Vets for us tomorrow.