I have a Forerunner 245 and last night when I was chilling and watching some Netflix, my heart rate monitor jumped to 160, out of nowhere. I checked my pulse and it was around 50. I woke up today and it told me my resting is 7 bpm higher than it usually is. It keeps giving readings 20bpm higher than reality. It has never seemed to have done this before, is there something I can do to help fix this, I’ve just cleaned my watch and made it tighter but it keeps doing it?