Bummer rebebarra! Not the best time for your phone to be acting up. When did this start? Did you download any apps recently that might be running in the background and draining your battery? Have you already tried taking steps like these: Battery life: Apple iPhone 6? Apple has their own iPhone Battery & Power page also, which includes the cost for replacing the battery without Apple Care+. At almost $80, it is steep, but maybe better than waiting two months with a phone that's turning off on its own.
You can check to see if your equipment is still under the manufacturer's warranty (one year from purchase as long as the equipment is still in good condition, or even longer if you have PHP/JUMP! on your line) - but if you're trading it in, exchanging the equipment will change the IMEI on your trade-in, which could lead to problems if you're participating in the iPhone 7 Trade-Up Offer. However, if you're just turning in your iPhone 6 as a JUMP! return, or keeping it, then it's not a big deal - just Contact Us and we can check out your warranty options!