Okay so background first to set the scene.
Recently my youngest sisters Xbox broke, our dog got out of the kitchen and chewed it, my fault as I was supposed to be watching him but got caught up doing house work. She was gutted as she just got it for her 12th birthday, I bought her a new one but I've got two weeks till payday so it's left me a bit skint. No big deal as all my bills are paid anyway. Just means I don't have any "spare cash" this month. My friend knows this yet has been harping at my all week to go out for drinks tonight, I've told her no and explained why again but she's literally texted me all day complaining that I'm being really shit and obviously don't want to see her etc. She's now started messaging my boyfriend and other friends trying to convince them to get me to go out and to feel sorry for her because I'm saying no.
Am I being unreasonable here for not going? I see her almost every week so it's not as If I cancel on her a lot or hardly see her. I'm starting to feel a bit bad for saying no now but I literally cannot afford a random night out drinking for no reason? :( she's normally a really good friend but has a hard time accepting no means no sometimes.