Generating Bug

This is a really serious and game breaking bug/glitch. Ok so i was planning to go to a woodland mansion in my survival world... I went there and it took thousands of blocks to get there. I used an elytra, went on a boat and did lots of walking. So after i found the woodland mansion i was heading back ti spawn when i realized the closer i get to spawn the more chunks that are not loading. I finally reached to spawn and when i reached there i started getting lag spikes like crazy! And when i was traveling somewhere else, every 20 seconds the world i was going to just stopped loading!! I would just have to wait about a full minute for it to load!! And the world size is 150 Mb so i don't know if it has to do with my world size or something but please fix this!! I am playing on a Asus Memo Pad 8.