I had super pretty curls a few years ago but for the past two years I have been straightening my hair and I wanted to start wearing it curly again but now my curls aren't and pretty and I have lots of straight pieces please help!
This sounds very similar to what happened to me (I straightened my hair almost everyday for a year). The first thing I would recommend to you is to find a good curl understanding stylist and get a trim. I didn't read what your hair properties were but my hair is very fine and the constant heat and pulling of the straightener (without my knowledge) had created some severe breakage and I had to get 6 inches cut off.
That being said I would start by babying your hair discover how porous your hair is (heat can increase porosity) and that can help you determine some of its needs as well as what to look for in products. I made a pact with myself that the only thing I would put into my hair for a year (for styling)would be conditioner and (I also got rid of sulfates, silicones) I can't tell you how much of a difference it made! I started out with a clarifying wash than a deep treatment (coconut oil) and from than on followed the rules above. At first my curls didn't want to for operate some were frizzy and some were nearly straight like you're saying (apparently excessive heat damage can destroy hairs elasticity). But slowly and surly it got better. Now it's been almost two years and my hairs never looked better! so just some encouragement too. It might take a while to find the right products and for your hairs natural curl to spring back but once it does it will be worth it.