You are a player on the New Jersey Nets basketball team.One day you read your team is on the brink of going out of business. The next, you are told your paycheck may not come. Then you hear hotels and airlines are demanding prepayment for rooms and reservations.

Your reaction? "You hit a psychological low," according to Howard Porter. "You wonder what you have gotten yourself into."

Porter walked into the current financial dilemma of the Nets when he was traded from Detroit. He is just catching up to what those players who have been with the Nets all season already knew:

The teams's indebtedness over the next 20 years is estimated at between $15 and $20 million. Owner Roy Boe's yearly debt is thought to be at least $1 million.

Attendance at the Nets' new home at Rutgers University is averaging fewer than 5,000 per game. About one-third of the fans have come for games against Philadelphia and Boston. Last year on Long Island, the Nets averaged 6,928.

Boe's salvation could be selling the club to the New Jersey Sports and Exposition Authority, the Sonny Werblin-run organization that plans to build the Nets a $45 million field house by 1980.

For many NBA officials, the Nets' financial nightmare is a replay of bad dreams they thought had gone away with the merger of the NBA and ABA. Once the merger was approved, the league was supposed to stabilize and clubs were supposed to prosper. But someone forgot to take into account the Nets' specific problems.

They stem mainly from that merger and Boe's own ill-conceived maneuvers.

For the privilege of joining the NBA, Boe and the other three ex-ABA clubs (Denver, Indiana and San Antonio) had to pay $3.2 million each. He also had to pay Knicks $4 million for putting a team in their territory. And when he decided to move to New Jersey, he agreed to pay another $4 million to the Knicks for locating even closer to Madison Square Garden.

Toss in the money he owes to the ABA players association for players who lost jobs due to the merger and the money he owes the owners of the Kentucky and St. Louis ABA franchises that did not merge and the money he owes on contracts of players he has either cut or traded and he is walking a precarious financial tight-rope.

Boe is supposed to fly out to the West Coast this week and talk to the Nets, who are in the second week of a two-week road trip. At that time, he is expected to tell them about a $1 million loan he has obtained from a New Jersey bank, about the group of small investors who are ready to inject new cash into the operation and about how a local civic club has pledged to buy out all tickets for the last home game at a cost of about $25,000.

But whether this new money will be enough to salvage things is debatable. There is some speculation that he won't be able to meet the next payroll, due Thursday. And it is unlikely his last-place team, the worst in the NBA, will draw many people into home games as the season progresses and the weather worsens.

Boe must blame himself for some of the problems. He had the best team in the ABA before dumping people like Julius Erving and Larry Kenon. Now he's left fans with little to root for, and he's left his players confused by issues that they can't effect.