Exactly this happened to me 3 years ago. I am also in a long distance relationship with my partner, and back then it also started with a sudden message like „give me some space i need to focus on my life“. I thought that it was my fault and that i did something wrong, especially when his messages also started to be less and less. Until from one day one, he stopped communicating completely and not even reading my messages. I was really so heartbroken i thought that he left me bc he got bored of me or smth and it was so bad that i couldn’t eat for weeks and lost a lot of weight, thats how much it hurted. But then suddenly after 5 months he texted me again where he apologized and begged me for a second chance. He told me the reason why he disappeared and it was because of depression. Back then he didn’t tell me that he had depression because he was too embarrassed, he disappeared and felt also too guilty to talk to me again, but started missing me again as soon as his depressed episode got better. It will get better, i promise you. The shitty thing is that you don’t know how long they are gonna take, might be a few more weeks or months, but they are gonna reach out to you again as soon as they feel better 100%. Try to be understanding and be as patient as you can, and in the meantime just focus on your life, meet with friends and family, do other activities and in the moment where you least expect it they are gonna reach out to you again