I think if you had a normal supportive growing up you had a chance to explore your interests instead of trying to survive. Now as an adult it makes sense to explore hobbies to try to find what speaks to you. I think it's kind of normal for hobbies to go in and out in our lives. I used to do a lot of beadwork but then I started writing a novel. When I am done with the novel I hope to return to beading.
Your spending doesn't sound manic. It's not a random thoughtless purchase if you are shopping for deals online. That means you are trying to stay within your budget and thinking it through.

What you do sounds normal to me. Also you don't have to stick with a hobby forever for it to be enjoyable or beneficial. My partner and I used to grow bonsai trees and spent a few hundred $$ om equipment etc. We stayed with it for about 2 years and had fun together and learned a lot. Ultimately we stopped because it's very HARD and we struggled to get our trees to survive and that was too disappointing. But I don't consider that time a waste. We tried something we always wanted to try and decided it wasn't for us.