Hello, looking at your concerns it seems that you have deep caries in your offending tooth and most likely the caries has reached till the pulp which explains the pain increasing at the night. It is best to get a consultation at your nearest dentist. If you get your consultation at the earliest then the tooth might be salvaged with Restoration or Root Canal Treatment. If you delay then you might experience tremendous pain in the middle of the night when you won't get any immediate access to a dentist. You might also end up needing extraction of that tooth.

Mostly tooth aches during sleeping is because when we lay down more blood rushes to our heads and put extra pressure and hence the pain. The pain could be because of the developing and progressive caries and has nothing much to do with your 2-3 weeks of eating chocolates if you were brushing properly. Only a proper diagnosis and treatment can give you relief.