gay relationship vent/advice

so my boyfriend and i broke up 3 days ago. we were madly in love so i thought. our first night together got hot and heavy and we eventually started having sex about 3 weeks in. from that first night on we were pedal to the metal. we made it official christmas day. we made mistakes and acted like we had already been in a relationship for over a year despite barely knowing each other for a month prior to our relationship. the day after our two month mark he texted me and said he needed space and i graciously gave it to him because i knew we had been spending a fuck ton of time together. we kept little contact for the next few days and then he got super distant and i knew something was up. i texted him this past thursday morning and said we needed to talk. we met at chipotle and sat outside and talked. he was burnt out and had already mentally checked out of our relationship. i was sitting there with my heart on my sleeve ready to make things better and slow down. guess i was too late. we met at work (starbucks) and now work is super fun. the worst thing about this is the fact that we ended amicably with no hard feelings or cheating to speak of. my heart is telling me there's a chance you two could end up together again. my brain is telling me i need to get over him. it's so early in the post breakup that it makes sense i still want him back. he recently posted a photo that read "how do you know when it's over? maybe when you're more in love with the memories than the person standing in front of you." pretty much killed me. i know i have to get over him, but how can you go from being in love one day, saying you want space the next, and 5 days later saying you're burnt out and don't want to continue the relationship.