Looking for Support

I am a 28 year old teacher, who lives in Texas. I am turning 29 in March, and my boyfriend and I are going to Costa Rica. I have gained about 10lbs in the last 4 months. I really want to lose the 15 lbs before our vacation. I would love to have some support. None of my friends are really doing this with me, so it is a little bit harder. Thanks in advance :-)