Hi Andrea,
Yes, trying to maintain a happy face despite how you are feeling is very hard to do. However, if you were raised that way making it a requirement it may be hard to stop.
Up and later crashing takes a toll on your body. It makes sense to me that you often are not able to sleep. Can you ask for some sleeping meds (but not depressants) from a medical professional.
Seeking help from a therapist also sounds like a good idea so that you can get your feelings out with support. That may help the major crash you commonly experience.
I hope that this helps...