I hear you friend. If I may I would like to share some thoughts on the both of the matters you mentioned.
Backup saves are always important, in construct this is even more so if you are saving to the browser. I would recommend you do a download save periodically. If you save to the browser then clear browser data it will delete your project. I'm not sure if your project is retrievable because I don't know every detail, hopefully someone else can help in that department.
As for the cost, there are free alternatives to C3. C3 seems super simple because it is engineered well, but it's a premium software and must be paid for by users, we (the users) must support it for it's survival and continued support. So like I said, there are free alternatives that you can use until you can afford C3.
Most important, please don't get discouraged from game development. It will always be a roller coaster ride no matter which technology you use and your experience in it. Though the lost project may sting you will never let it happen again and will be a better developer for it.