iPhone screen flashes apple sign when I plug in then press home button

Hello,

I haven't had any sign of trouble with my iPhone 6s until yesterday. I plugged it in as I went to sleep. The phone was on but the charge stayed at 1% for awhile. I didn't think much into it. I woke up to find it still at the same charge. It died. I plugged it in again and my charge began to rise. Today went by with no issues until this evening when it died at a very high charge like 70-95%, at least that is what I thought it was at. I went to plug it in thinking it would charge back up. Having left it to charge for an hour or so, I went to grab my phone. It turned on briefly with the charger still plugged in, say 2 minutes. I didn't look at the charge it had but my phone shut down again. I tapped the home screen, curious as to why this was happening, then the screen flashed very briefly,(<=1 second). I did this a few times, with the same flash result. My phone stopped responding after I took it off of the charger. I waited for about 10 minutes then plugged my phone back in. With my phone plugged in, the screen flashes the apple sign in continuous intervals. The screen will be on the apple sign, go black for a couple seconds, return to the apple sign, then the process repeats.

I have tried searching for my exact issue, but no answers seem to identically match my issue.

Sorry for the novel. Any help would be greatly appreciated, especially if it doesn't result in my buying of a new battery... Thank you!