Help needed to maintain weight!

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Hey y'all! I've been maintaining an 80+ pound weight loss for a couple of years now by counting calories and working out five days a week (cardio five days, weight training three days). I started at over 220 pounds and finally stabilized to maintain at 138-140, and stayed happy there. I was eating about 1,800 to 1,900 calories a day, every day.

It was all lovely and fine. Until January.

At that time, I went off the birth control pill, and things have just gone haywire. I kept working out five days a week and eating my regular amount of calories, but my weight started creeping up. From 140 to 141, 142, 143...now I'm bouncing around these days from 144-147 and I do NOT know why!

In an effort to figure things out, I've come to My Fitness Pal on a recommendation. I'm wondering if I was working out TOO much for what I was eating, so I cut back to three workouts a week, cardio and strength (M, W and F), and I'm gonna pick up something like yoga on Tuesdays and Thursdays, starting this week.

I see on here that I'm supposed to "eat back" my calories, but I'm SO scared to!

Anyway, any help you can give me with this problem would be great! Should I just bite the bullet and start eating back my calories on workout days???