I couldn't quite follow the BR explanation (you sized your bets based on a $5k BR, but then went to the casino with $2.5k?), but no matter--it does sound like you way overbet. Put it this way: regardless of Kelly or any other numbers, if a single-day loss is big enough to (1) make you depressed, or (2) jeopardize your future ability to play, then you are betting too much. Losses should cause irritation, not depression. This irritation should lead to more intense study and work. After every major loss of my career, I worked twice as hard on numbers research to improve my edge for the next session, to reduce the chance of future irritation.
With the $5k (or with the $2.5k remaining), you should wong as much as possible. Backcount and enter games at good counts, and walk away when the count is bad. If there are not enough tables to do this, then you should at least take frequent bathroom breaks to avoid playing through negative shoes. You can't afford to take swings on negative counts.
You might also consider working with another counter in your area, if there are any. You would feel the support and camaraderie that you are now missing, and probably also realize faster what weaknesses you have in your game. (Be aware that partnering with another counter probably would cause additional friction with your SO, which has thus far gone as I unfortunately predicted--with his belittling you out of a need to maintain his own mental superiority over you. I think I won the pool--ChaCHING!)
Remember also this life lesson: money is the most easily replaced thing (with bad boyfriends being a close second!).