Sorry to hear about your inconvenience. It must have been frustrating.
The oft-repeated lesson herein, regardless of the airline - but especially on a commuter feeder with a reputation for lousy ontime service into a hub known for disrupted schedules - is to avoid last-flight of the day connections wherever possible. (Especially on Saturdays when reduced schedules may be in effect).
Even under the best of circumstances your apparent itinerary seems risky with just a 38 minute connection at EWR. Given the propensity for short-in flights to EWR to face delays, that's a window without breathing room.
A quick look at the schedule out of Boston indicates that there aren't any post-6 p.m. options on alternate carriers that would have gotten you to Vegas last night except a single JetBlue flight. Hope you made it safely today.