You have had some great responses to your post and I don't have much to add to what they have already said. This behavior is very complex and at the level of a crossdresser it can definitely exhibit an off and on type of pattern with periods of uncertainty mixed with periods of certainty and high confidence. At the level of full on transgenderism where the person rarely has any feeling other than they are female-like if male sexually or male-like if female sexually. You are light years from that kind of identity structure.

The main task at the level you are at is to react to whatever urges you have in a way that feels right in its consistency with the structure of your sense of self at that time. Sometimes just little things can be affirming to yourself, like a dab of fragrance on your upper lip if you respond strongly to feminine aromas. If the contrarian demons go to sleep then you are on to something that is calming and satisfying even though it is a tiny thing.

Going out in public is not necessary but it does add a completely new experience and can be affirming if you are among people who are accepting; it can definitely alleviate the uncertainty you may feel regarding yourself. Even one sincere "Mam" can put you way beyond Cloud 9 in affirmation of your identity in your sense of self. But not everyone needs that public affirmation. Experiment, try new things. If they go well add them to your purse; if they go badly recognize that acceptance is not guaranteed but is individualized.

Depression doesn't help and is a possible big factor in your comfort. Shift your behavior around and see how it feels. If it fits incorporate that; if it doesn't try not do that again. But always keep in mind that we are each like a piece of Silly Putty - we are not fixed and can take many shapes and forms. But some things fit better at the time than others and that calls for experimentation to find the comfortable form for you. Turn that experimentation into a fun journey of exploring your deeper self. Keep a diary or journal and read what you wrote before often enough to refresh your memory about all the variations you have gone through. Think more in terms of the present rather than being goal oriented because life is lived in the here and now and not the dreams of what could be. Have fun; if it isn't fun don't do it.