Since you lost 18 pounds you might need to lower your caloric load a bit. Also, you might count your calories for one day to make sure you're not eating too much. You should be exercising 6 days a week. Eat lots of green leafy veggies and drink plenty of water.
Your body may just be adjusting to your new weight for a bit so try not gaining while plateauing and you will continue to lose eventually.

Thank you for the advice. I have been trying not to be discouraged. I will count calories this week and up my exercise. Anythings worth a try. I know I have been slipping on the weekends due to traveling. I have been able to at least stay with in 1-2 lbs of where I was and then slip back to my 18 Lbs. I have been an extra 45-50 lbs for the last 20 years, but I will be honest. When I realized I could not get off the floor after playing with my 2 year old grandson, that was all the motivation I needed to get started.

I have that same trouble, plateauing. I lost weight at a good clip for several months, then things started happening. (Birthday parties, mother in law moving in, ...)

So it is time to renew the attack on those extra pounds!

Plateau happens! So I recommend tons of patience and do not get discouraged. Recheck your portions...maybe you need to get re-aqauinted with what a serving really is rather than guess at it. Also change your exercise...the body gets used to the same moves every day and adjusts to it so throw something new at it so it has to re-adapt. Our bodies are very clever at surviving and conserving those energy calories.
Let us know what finally worked for you.

Thank you for the encouragement. I found a used treadmill that has preprogramed workouts and started doing that 3 times a week along with my exercise band work. I appreciated the encouragement, this is where I really usually drop. I also started measuring my food again. I realize that my portion control had slipped. Thank you!