Toxic Relationship and Finding My Way Back to Guidance

Assalamu alaikum, I really need to get this off my chest and hope someone can understand. I was raised in a Muslim home, in a Muslim country, and I used to be fairly consistent with my prayers and everything. But then things changed-I don't know why, but praying started feeling so heavy, and I just stopped. Last summer, I got involved with a man, and since then, I've completely lost myself. I've been drowning in sins, astaghfirullah, like so many. It's bad-I barely fasted this Ramadan, and even broke my fasts in sinful ways. I look at myself and I don't recognize who I've become. The relationship itself is terrible, so toxic-it's just brought me constant stress, tears, and I'm always twisting myself to please him, scared of upsetting him, bending my own morals. But at the same time, I feel like I love him and that my world would collapse if he left. Lately, I keep getting these reminders from Allah about death, like signs to turn back. The guilt is crushing me, I don't know what to do anymore.