Lost only 3lbs in last 3weeks

Hello Today I'm feeling a little blue in the last three weeks I have only lost 3lbs. I am still walking and I bought a excerise bike this week with a lateral thigh trainer. I hate that my weight is not coming off as fast as others. I would like some suggestion. The summer is fastly aproaching and I would like to look nice. I want to ride the rides at the amusement parks this year. I don't want to be scared that I won't fit in the seat. I also want to go out of town but I'm scared of being chared for two seats. I am still at a weight that they can charge for two seats. Bonnie