If you were at 120 lbs before, that weight could be your body's preferred set point. After recalibration due to hormones the body could be trying to get back to that point.
If you were stable at 120 lbs you probably had an equilibrium. As you continue to lose weight, your caloric/energy needs decrease as well. At some point you should hit balance, where your energy expenditure is balanced by your energy intake, hormones, metabolism etc.
As others have said your weight loss was/is pretty slow. I experienced something similar. Going from 165 to 135 over about 9 months.
Once I added in progesterone my body lost 5 lbs, going from 140 to 135, and has since stabilized. Not really affected by how many calories I consume or activity level.
The calories in calories out is vastly oversimplified, as your body does a lot to regulate weight.
I would not recommend starvation mode as that can permanently affect your metabolism. Just look at the biggest loser contestants- having to eat hundreds of calories less every day to maintain their weight; in comparison to someone who was always at that weight.
Definitely get everything checked by a doctor.
Maybe consider checking your "typical caloric needs" through a bmr calculator- gives you a ballpark figure. From there examine your lifestyle, activity level, and food intake. You could try an app like myfitnesspal- free.
Also look at the rest of your health, are you feeling good, energy, sleep, mood, stress etc.
~Brooke~