Lending my bf money

I’m all for lending my boyfriend money when he needs it, I’ve lent him about $500 to help pay for his truck when it came out of the shop and now he’s trying to go back to school and he has to pay off his last semester. To do so he needs to borrow around $1,400 from me which I have worked my ass off to save and is only gonna leave me a couple hundred in my bank account. Im in no way complaining I have no problem helping him we’ve been together for 3 years and we’re here to help each other and I’m all for wanting him to go back to school and everything I’m just a little pissed that he decided to wait till like two days before school starts and I know it’s selfish but I’m paying off school too and have payments and I’m really gonna be stressing about money now cause it was a safety net for winter when I’m working less hours as it’s my “off season” I know I’m being selfish but I feel like it’s understandable . Or am I being unreasonable?