>Probably a lack of protein.
Buy protein powder. Try to avoid flavored powder, even if you like it the first few times, because you will get sick of it. If you think you still want flavored protein powder, also get non-flavored one so you can "dilute" the flavor of the flavored one.
Stop drinking anything other than water. It sounds hard at first but it saves you a ton of calories. Milk is also fine sometimes if it is never more than one glass (a lot of protein powder also comes recommended with milk).
Also be sure to eat a lot of chicken and other high-protein meat.
Intermittent fasting is also something I can highly recommend. I only eat every other day and it helps constraining calories a lot. Be sure to plan your meals for food days and to stick to the plan.
Running really is great. Unexpectedly, I like it a lot more than lifting now. I don't know how dangerous your streets are, but if you are anxious, just take a pocket knife or a gun with you if that helps.
After a week or so of running you will notice that most of your limits were only psychological and that you can push yourself much more than you previously thought.
As >>139756 pointed out, there are also a lot of other very effective workouts you can do even without equipment.
Those last 20lbs are not going to be that hard I imagine. A friend of mine went from about 180lbs to almost 145lbs over the past three months. Regularly checking in with somebody who has your back can help a lot in this process.
Never forget not to fall into fallacious thinking. If you eat one piece of pie, you cannot give yourself permission to eat the whole pie.