First off, I think it's very pretty. I've always loved the tulip quilts.
I'm going to agree with everyone that I think a border would be great to finish it, but I'm not going to agree with the blue. I didn't actually count the tulips, but you do have a lot of blue already in the quilt. Blue is an incredibly tricky color, it can illicit feelings of happiness, but it can also bring a person down and 'give them the blues', I think that might be the problem for you, the blues you have in this quilt are muted.
Quilting is already a challenge, sometimes we find ourselves not liking a quilt because of the colors we chose and usually not the reason we believe it is, i.e. for the overall look of the quilt. Color plays a huge role in our moods and emotions; too much red makes us excited, the wrong shade of gray makes us sad, etc. etc. Red and green together actually pulls my holiday blues out in the middle of July and I'm panicking and full of anxiety until I go find other colors to look at (usually an ocean blue, that calms me down). My family actually does not like shopping for fabric with me, because of my visceral reaction to red and green. By themselves, I don't have a problem, but put them together and I'm a mess. Like hyperventilating, uncontrollable shaking kind of mess.
Might I suggest something different. Maybe yellow or even a yellow-orange, bring it up to someplace 'sunny', if you're following my direction (I hope so, lol). Find something away from the palette you've already created and bring something in that is happy or joyful. I think once you do that, you're going to find your mood shift will actually help you come around and you'll love the quilt again.