@SkillfullLemon6127, in my opinion it is completely normal. The depression is a mood disorder which means it can vary depending on the hormones and current neurotransmitters' sensitivity and environment and stressors and all of the different things I don't know, because I'm not a professional ^^
But your experiences sounds a lot like mine, to be honest. Those constant fluctuations made me think that I don't have any real problem at all and sadly hold me back for years from seeking needed medical help.
Depression is not being sad all the time. Your brain is constantly fighting with this illness and when you have better odds, it wins. I'm glad to hear you're having a string of good days, too, lovely. Please take the best care of yourself now, so you don't have to suffer any longer from the harder times. The sooner you address this issue, the sooner you will feel better.
Sending lots of hugs!