I'll be devil advocate since I've done what you're friends did once. You're right btw. Friends can have their alone time and 100% NO FRIEND SHOULD FORCE friends to be with them or tell them everything. STILL it is possible doing this without hurting the one that is left out. if they can't sense you feeling uncomfortable, left out and hurt the whol......
Break contact with them. If they didn't even try to talk to you during those weeks of not communicating, then they probably don't want to be close friends with you anymore. They didn't even try to include you in their hangouts together so u don't have to feel bad for trying to sever ties with them since their actions doesn't exactly reflect that th......
time to get new friends girl... i think they're trying to "show" you how close they are
They're hinting that they don't like you, no other reason to be that tactless. They absolutely do not want you around trust me girl. are you enn RUN

Feeling left out, and miserable.