Growth spurt or just teething?

My sweet, little five month old girl just got her first tooth last weekend. It's stinkin' adorable and a little crooked, which I love.  She was teething for months prior and it broke my heart. The last couples days after the tooth broke through her gums have been rough too, but she has been behaving a bit differently. More clingy and lots of sad cries. Nights are all outta whack too now. Tonight she ate for two hours off my boobs straight. Two hours. Every time I tried to put her in the crib, she would cryyyyy. Finally at 9:00 (two hours since I started feeding her) she stayed asleep in her crib. Has anyone else experienced that with teething or could we be going through another growth spurt? At her 4 month check up, she was 18.5 pounds and 26.25 inches, so she is a bigger baby! We haven't started solids either! I am thinking closer to 6 months, so in about three weeks.