Oh dear, confused - you are certainly confused about the reasons why you want to have a baby. There is no guarantee that your child will love you, and certainly not "always" love you - people don't have children as companions. I think you need to think about your priorities.
The GP will almost certainly suggest you keep a chart of your periods, if you don't know when the last one was. It's necessary if you are trying to conceive. Please do consider why you are doing it though, babies are expensive, highly demanding, very hard work, not all cuteness and cuddles.