Thank you for listing out your questions.
Here are my thoughts:
It sounds like you and your bf were enjoying an intimate emotional connection when he started pulling back, citing depression. There are a couple of things that could be happening and I want to honestly share these with you. First, it is quite possible that he is in the throes of a deep depression and feels that he doesn't deserve you and it wouldn't be fair to make plans into the future with you because he is not worthy of you - and this part of him might be making him feel "trapped" when you refer to "us" or "we". Another possibility is that he has some concerns/issues with this relationship but lacks the communication skills to appropriately bring it to the forefront and as a result he has turned to being avoidant and is consciously or subconsciously moving away from you in this way. In either case, it is clear that this is not a healthy pattern for the relationship.
I can imagine how hurt you're feeling because his depression suddenly seems to have turned against you - and you're suddenly at the receiving end. This can be a very hurtful place to be in. I would encourage you to bring this up with him. This answers your second question about protecting yourself. You absolutely have a right to protect yourself and his depression should not result in pain to you. I think you did
the right thing by reaching out to him through an email and suggesting that you and he not talk about the relationship till he was feeling better. I think what is important here is gently laying out some boundaries of what is acceptable to you and what is not. I also think it will be good if you encourage him to be forthcoming about anything that might be bothering him. For example, the statement about career and choosing you - what is leading him to think that he must make a choice between you and his career, why does he think that a relationship with you means it will be at the cost of his career? These are questions you need to explore with him to understand why or what is leading to them. I would also encourage you to tell him to take some time and think through these issues, before further discussions are made about the relationship. This will lead him to take ownership of the issues that might be troubling him and start looking at them instead of pushing them away.
You can also articulate that he is welcome to discuss all these concerns openly with you, but until these are worked out, it is best to put the relationship on hold. This will give him a clear message that it is not ok to be avoiding you while at the same time receiving love/attention from you. That he must make choices and decisions and cannot leave you hanging and waiting.
If he is still severely depressed in 2 weeks I would recommend putting a hold on your trip because it seems clear that particular issues are at the core of his depression. Until these are addressed it may not be a good idea to visit him.
I hope I was able to answer all your questions. Please let me know if you have any clarifications/thoughts.
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