with the being really tired thing after a ride - since you've only been riding for a month, your body could still just be adjusting to the demands and stresses of the sport and is nothing out of the ordinary. your body probably got a little bit of shock from the 4 days off and then a harder than normal ride for you. perhaps you didn't have enough carbohydrates in your system and most of your glycogen stores were used up...could be not having enough electrolytes...could be that you pushed at a higher intensity for a longer time than usual. this causes your body to create a higher demand for physiological adaptations and will effect you by being tired, sore, hungry, etc. these are all good things because they're signs that you put a higher stress on your body and it therefore needs to adapt to handle these additional stresses (i.e. you get better).

there are many possibilities as to what caused you to totally crash after your ride but i think it's mainly because you're still new and your body is still getting used to it. when i have rides that are above my normal intensity or volume, i get tired too! it's normal. it's okay