Losing streaks are part of "Playing Football."

I should know. I've had one every season for seven years and this year is no exception. The 1980 ledger, despite a promising start, currently stands at minus $1,890 after last weekend's minidisaster.

It is particularly important, during a dispointing string of selections, to recheck the reasoning behind any major losing picks. As, for example, Sunday's $550 loss with Oakland giving 7 1/2. Was it a sound selection or a poor one? The Raiders won, 16-10, over Miami.

Keep in mind that many times during the season, a bettor, any bettor, wins for the wrong reason and loses despite having made the proper choice. Oakland on Sunday was a good selection. The Raiders held Miami to 63 yards rushing and 103 yards passing, while compiling 192 and 137 yards. They outplayed the Dolphins by a much wider margin than the final score indicated.

Such is life in attempting to cover the point spread.The important thing during a losing streak is to stay resonably cool, to accept what's happening as part of the game and, above all, to resist the temptation to double up and catch up. There are 20 weeks in the betting season for professional football. There is plenty of time. Don't panic. I was down $3,865 last season and still managed to keep the perfect record intact.

This week's card offers several interesting situations. Chicago, Los Angeles and Houston will attract imaginary plays of $500 each, while $250 rides on Minnesota, Oakland and Green Bay. The Bears have an excellent defensive unit, including a front line that's second to none in the matter of applying pressure to a passer. Washington's offensive line has been hurting all season and the Redskins lack a reliable runner. Joe Theismann could be in for a punishing afternoon. The only danger in giving the three points is if Vince Evans' passing is more erratic than usual. Certainly, Walter Payton figures to have a fine effort. Everyone runs on Washington.

Miami's offense is sad. The Dolphins have scored 123 points in nine games and yet somehow are 4-5, a tribute to their good, overworked defense. This is a team without a quarterback, even though it has three in a rookie (Woodley), a never-will-be (Strock) and a banged-up veteran (griese). The offensive line also is a far cry from what it used to be. L.A., meanwhile, possesses the best-balanced offense in the NFL. The spread is high, at 10 1/2, but playable.

New England-Houston provides one of the best matchups of the year. The Oilers are favored by 3 1/2 in the Dome Monday night. Earl Campbell figures to enjoy another excellent effort. He is carrying Houston while Ken Stabler struggles to bring consistency to the passing attack. Steve Grogan could make this selection backfire, should he have the kind of performance he enjoyed against Baltimore three weeks ago. But Campbell is a sure thing while Grogan is always something of a question mark.

Minnesota faces a must-win situation as a one-point favorite at home against Detroit. The Vikings are two games behind the Lions in the NFC Central. Detroit defeated Minnesota, 27-7, Sept. 28 but the score was 10-7 in the fourth quarter. Since then, both defenses have played well while the offenses have sputtered at times.

Oakland's defense continues to impress. Like Chicago's, it is very physical, although terribly showboaty in the secondary. All the Raiders must do in order to cover against the Bengals, giving 6 1/2, is for Jim Plunkett to stay away from the three interceptions he put up against Miami. Green Bay has become surprisingly respectable during the past month. I like to go with a young team just beginning to realize the joys of victory. The Pack is such a squad, while San Francisco appears to be wearing down gradually after its 3-0 start. I'll give four with Green Bay at home.

In other games, Las Vegas lists Atlanta two at St. Louis, Buffalo 3 1/2 over cleveland, Dallas 10 at the New York Giants, San Diego eight over Denver, Seattle three over Kansas City, Philadelphia 10 at New Orleans and Pittsburgh 6 1/2 at Tampa Bay.