Someone suggested you may not be able to access all posts due to many posts you made. I have 150+ posts started in January and can access my first posts still. Have also a lot of comments. Total a bit less than you, but not more than 800 less (post+comments).
I noticed yesterday some troubles with the Steemit servers, HTTP 503 error several times, also some days ago had same error in browser several times. Should not have to do anything with your problem, but maybe Steemit Inc is updating patches to the software and causes UI filter errors?
Did you try another UI to Steem blockchain? Busy.org or eSteem App/desktop client?
That's too complicated:) I think I'll wait for a couple of days to see what will go on