Marketplace invalid Session, skin not loading and online broken.

When I start minecraft and I'm in the menu waiting everything to load, my skin doesn't load, the marketplace says "invalid Session (try restarting your game)" and I can't join servers because they say "coming soon". My account gets signed in tho. Sometimes they load anyway but I haven't tried joining them. I can invite people into my world but it doesn't work for them. One time I tried to enter a world (while my minecraft being bugged) and then my minecraft crashed. I restarted minecraft and everything was fine. But only for this one time. The next time I started minecraft it was broken again. I can't play online with this bug. Pls fix. Thx.