I have been having sudden heart rate increases while sitting.

Needs evaluation.: Sudden heart rate increase while at rest is not normal. However it is unclear as to what the actual heart rate is or whether it resolves on its own. An unexpected increase in the heart rate while rest warrants a detailed history, exam and possibly rhythm monitoring. If the rate increase is mild, eg. from 60 to 90 beats per minute, it may be benign. Would recommend that you seek further evaluation

Could be normal response such as being amnemic, or stress. Alternatively one might consider arrhythmia, autonomic dysfunction. Suggest holter monitor if daily or an event recorder if sporadic. In the interim see if the puke is regular and is the onset gradual or instantaneous.