Deleting apps when changing battery

That doesn't sound normal. I remove and return the battery on mine and all I have to do is wait a minute or two for the phone to finish scanning the memory card and I'm back in business. But, I have heard of this problem affecting someone else.

What you can do is get yourself a good backup program that lets you save to external sd and set a backup schedule. For me, this is the best insurance so you always have your files secure. I know this doesn't solve your main problem but it's definitely more convenient to just restore than to install everything one by one.

Another thing you can do is try a factory reset. Hopefully that will clear out whatever bugs you got and things will get back to normal.