[22M] [24F] My boyfriend suddenly cuts off contact with me and I don’t know what to do

We’ve been dating for 4 months. We text regularly and fall asleep on the phone together every night. He likes to call me by cute nickname: baby girl, my angel, the love of my life. He is the sweetest and most gentle human being I’ve ever meet. But then suddenly 2 days ago, he changed into a completely different person

I say, something might happen at work. He always comes home right after work. But that day, he got off work 30 mins later than usual. He was still normal when he got off work. But when he got home, he texted me “I feel like shit so ima go get McDonalds”, I asked him “Why you feel like shit? Are you ok bae?”, he said “Please. Just give me a minute to think without you. I love you”. After that, he starts sending me dry texts and never calls me again. He stops calling me by cute nickname and doesn’t say “I love you” back when I say I love him or I miss him. Last week, he told me about his coworker - Abby. She had a very rough week: her boyfriend broke up with her, her grandfather passed away and she had to fly to another state for some important work. My boyfriend sympathizes with her so much that he even cries for her. I think maybe something bad happens to Abby that affects him. I could be wrong tho. I really want to drive 3 hours to his state and figure out what’s going on. But I’m also afraid he might get mad at me for meddling in his business. Should I give him space and wait for him to get back to normal? Or drive there and find the answer I need? Is it normal in relationship that your partner cuts off contact with you without a reason? How can I let him know that I feel worried, sad and lonely when he leaves me in the dark? Please let me know your thoughts about this. I really appreciate all the advice

TL;DR: My boyfriend suddenly cuts off contract with me without a reason. My guess is that something wrong happens at his work. I want to drive there and figure out what happened but I don’t know if I should do that

Edit: I'm 22 and he's 24. I met him online and he drives 116 miles to meet me every month since we started dating. He is very sweet, responsible and mature. He helps me grow as a person. I’m ashamed to say this, but I’m a full time student and I don’t have a job. That makes a huge gap between me and him because I lack experience of everything in the world. But instead of leaving, he chose to be with me and willing to fight for this relationship to work. I trust him, he never cheats on me and I believe that he has a reason even when he doesn’t tell me. Maybe he thinks that sharing his problem will make him “weak”. I gave him the space he asked for and waited for him to talk with me again. But I started to lose my patience and felt anxious. I have no one to talk to. That’s why I write it down and ask for advice. I haven’t told him any of this, y’all told me not to drive to him so I wouldn’t do it. Hope he doesn’t keep me waiting too long and I expect he explains everything after he gets back to normal

Update: Actually it’s nothing to do with Abby. I have abandonment trauma, I fcked up by saying how miserable I will if he leaves me and now he feels like I emotionally manipulated him. I know I’m a fking trash dump and stupid. But I swear I didn’t say that to trap him. I make mistake and I very regret it. How can I fix this?