Am I working this hard to be at maintenance?

I'm getting a little overwhelmed and am on the verge of throwing myself a nice little pity party.

Here are my stats/brief history:

46 years old
CW 146.4 (have gotten to 143.3), GW 142
5'9" tall
have my goal set to lose .5 pounds/week, so I eat 1670 calories/day (with macros set at 35p/35c/30f) plus my exercise calories that I determine using a HRM (I don't eat them all back to allow for error in calories eaten, but always make sure I net at least 1200 calories)

I lost 45 pounds from Jan 2013-May2013 with the Ideal Protein diet. From the end of May until now, I've been using MFP, so I've lost anywhere from 17-20 pounds as well as a few more inches (I have not lost any inches since the beginning of December). Since the middle of Jan, I've been increasing my strength training. I focus on my lower body/butt 2x per week with tons of weighted squats, lunges, bench steps, etc. Each time I either increase the weight or add a few reps. 2x per week I focus on my upper body, again increasing weight or reps. I also do cardio (Zumba, spin class, machines or walking) almost every day (except the days I do lower body work). I do understand that strength training can cause water retention, but shouldn't I be seeing some results somewhere? My tape measure hasn't moved in over 2 months. My scale only seems to gain and lose the same few pounds (which I know is typical) since the very beginning of Jan where I saw the low of 143.3 just that one time. Prior to that, I had plateaued for about 6 weeks, after coming off another plateau of about 4 or 6 weeks. It has taken me over 4 months to lose 3 pounds.

During the week, I am pretty careful about my diet. I eat lots of lean protein and fresh vegetables, with some whole grain carbs, fresh fruit and dairy. On the weekends, I often indulge in a meal out, but I am rarely over my calorie goal, and if I am, I've usually "banked" calories from the week. However, a meal out usually results in a 2-3 pound gain (I know it's water retention, etc) which takes the whole week to lose and then the weekend comes around again and I'm stuck in this cycle. I know the obvious answer is to not have a meal out, but my concern is not necessarily getting to my goal weight. My concern is am I working this hard to be in maintenance? According to various calculators, for someone with my stats, for maintenance I should be allowed around 1900 calories (plus exercise calories. I use "lightly active" in order to keep myself motivated to exercise to earn calories). If I'm basically maintaining at 1670 calories and exercising like it's my job, what's going to happen at 1900 calories and I can't keep up this level of exercise?

Should I continue as I am and hope to see some kind of result? I haven't had any measure of success since early Jan. My clothing fits exactly the same since September/October and my measurements haven't changed in 3 months (and then it was 1/4 of an inch). Am I just on an extended plateau? Or should I try upping my calories and see what happens?

My diary is open. I don't track my water intake, but I always drink at least 80oz/day, usually more. Any advice, support, commiseration, etc would be greatly appreciated.