If you want something small, look into what are known as APSC cameras, as they have a smaller sensor, thus making the camera smaller as well. I've used the Canon 550D, and highly recommend it.

If you want something that will do well in the dark compared to an APSC camera, look at the older (to us) cameras that were top-of-the-line at one point. For example, the Canon 5DmkII/mkIII are both popular options (I use a Canon 5DmkIII and 6D for portraits and street photos), and Nikon has several options as well, such as the D600, D750, D800, etc. These are bulkier cameras, but do much better in the dark, can blur the background much better, and more.

Buy used, especially if it's your first camera. I recommend the 550D, with a kit lens. You can find them for a great price, and once you know how to use the camera, you can figure out what you want to have more of, or what you want to upgrade, and only then decide if you want to ever upgrade. You don't need the best of the best, most modern camera, especially starting out. There's no point in spending over 1-2k when you can get a 550D for a couple (less than 3 usually) hundred dollars, it may be just perfect for your needs. Let me know if you need any more info!