he threatens to cut my college funds
It's a terrible blackmail, people don't realize the pressure they put on others...
When you have the opportunity to be alone, let yourself cry, and when you're not alone, avoid thinking about what makes you sad, snacking can sometimes help, you can also express your emotions here via 'venting', if you want to talk about it don't hesitate, if you have less heavy on the heart, it will be easier for you to hide it, I wish I could help you more but emotions are always chaotic and are variable for each. To speak less rudely, you can speak slowly, this gives you time to think, and when it's possible, speak little, the less you speak, the fewer mistakes you will make.
I hope you'll find the peace you're wanting.