I'm new here, don't understand TDEE & needing advice...

First off...I am VERY excited my trainer recommended MFP to me & I'm thankful to be a part of this GREAT group where I can learn valuable info to help me reach my goals :flowerforyou:

Ok, so here's my quick story... I'm a 43 yr female 5' 7" currently at 177 lbs with a goal of 145-150 lbs

On Jan 28,2013,I began my healthy lifestyle change by eating clean & joined a gym. I weighed in at the gym at 180 lbs & had a body fat % of 37.4. Gave up my daily routine of having 2 Monsters for breakfast followed by 8-10 diet mt dews thru the day and only eating when I came home from work around 9pm which was crap food needless to say. Upon joining the gym I treated myself to a personal trainer for a year & do strength training 3 x's a week & take 2-3 cardio classes also. I've been 100% true on my diary and staying close to 1200 cal a day. I don't add in my exercise or eat more on the days I workout on MFP because 1 of the trainers told me not to worry about it but I am beginning to question that now.

I don't understand how to calculate my TDEE...I have read about it on here but feel a lil confused on all the lingo that I don't understand yet. I am happy that I have lost 3 lbs & 4.5 overall inches but feel a bit discouraged that after almost 2 months of dedication, I should be seeing more results.

After DAYS of reading posts on MFP, I'm thinking that maybe my body is needing more calories to see more progress??? Maybe I'm in a semi-starvation stalling mode??? If someone could be so kind and help me understand how to figure out this TDEE info, I would greatly appreciate any and all advice. Have a blessed and great day!