Plateau Help needed :(

concerto3

So, I lost my first 50 or so pounds purely by diet changes alone, maybe exercising slightly more than I did before but I certainly didn't join the gym. I didn't restrict calories in any way either, and have been tracking on MFP for only about 25 days straight now.

I hit 181 for the first time back in Late March, and I joined the gym in about February, but I hadn't really been going regularly until the end of April. Now I've been going 4/5 times a week for at least an hour, and doing mostly Strength Training and very very little cardio. (Maybe 0.5 miles/5minutes on a machine to warm myself up) I still haven't lost a pound, and according to my measurements, I haven't really lost any inches to speak of either. I feel like I'm just spinning my tires here. I keep bouncing between 182-185, which comes and goes on a daily basis almost.
I had my calories set at 1800, 1400, 1150 and still nothing regardless of how much, or how little I eat. My BMR is about 1635 or so, and I keep reading that I should be eating at least that, but will eating more even help when I wasn't restricting calories in the first place? I'm really at a loss here, no idea how much to eat, and I'm working out a lot more than I ever did before and I'm just not seeing any results. It really just makes me want to give up some days. Help?