My iPhone is using obscene amounts of data

[bkends35]

Long story short I somehow managed to use 5gb of data in 12 days on my billing cycle. I've been very consistent around 3.75gb over 30 days during previous years. I've been doing some testing by resetting my data counter in settings as well as using a third party app and my phone is using a ton of data. I just did a 1 minute youtube video test and it used 30.2MB over 1 MINUTE of SD streaming. Usually SD video is about 4.2MB per minute from what I've read. I also streamed spotify for 20 min on the way home from work on 96kb/s (I know for a fact it's set to this) and it used 58MB with 20 min of low quality music streaming. This seems extremely high. My usage pattern hasn't changed and I don't understand how I'm on pace to use 5x the amount of data this cycle. Anyone heard of anything like this? Or could anyone play a 1 min youtube video on their phone over LTE and see how much data it uses in settings? Thanks a bunch.