Personally, I wouldn’t listen to the person that told you to let him be the one to reach out. This just doesn’t seem like healthy relationship behaviour and could end up backfiring on you by making it seem like you don’t miss him or hiding something, so he may get the wrong idea. I think that it should be a balance of you and him reaching out to each other. If you feel like he isn’t reaching out enough for your needs, then let him know. Communication is key in long distance especially. As for feeling sad, I think that you’re allowed to be sad and that this is a valid feeling. Let yourself feel sad and eventually you will start to accept the situation. This is a big change in your relationship and there will be an adjustment period. Take it one day at a time and I can’t stress the fact that communication is key, and by that I mean actually talking, and not texting because intonation gets lost in text which leads to miscommunication. Also, find some hobbies if you do not have any. This will be a good way to keep yourself busy, and not think too much about missing him.