press your seams to the dark side, and pin the seams together when you get ready to sew. I also think the tension is to tight. Don't give up, you are doing great for a beginner!!! measure your squares to each other before sewing together and trim if need to so they are the same size.
Now just breath deep and relax! LOL We have all been there where we are so upset with what we are doing, it's just a part of learning!
You have chosen beautiful fabrics and they compliment each other well! So, you do have an eye for color and that is important!