Maven, this is a difficult response to hear, I know, but it must be said. Your boyfriend is part of the problem. He is what is called an enabler. And yes, this is a form of abuse. Someone, quite frankly, needs to intervene. You both need some help. This is a mental health issue. In some communities there are supports available for just such a situation and need. The start though is to do something about this relationship. It sounds to me like you might be hanging onto your boyfriend in the very same manner you are hanging onto things. The breaking an emotional attachment to things may very well need to start with him.

So reach out to your mental health association and see if there is an agency that can help you with the clean up. Sometimes fire departments can offer assistance with this.

Set some goals - small ones. instead of thinking that you have so much more to do, celebrate the fact that by accomplishing whatever you did on one day took you a step away from how things were.

In the meantime, take some of the earlier advice on how to do a search for a new accommodation situation. Finding a new place is an opportunity to start on fresh ground. But, realise that this won't solve the issue; that, you need treatment else this is all going to happen again.