[halotrope]

I have similar dynamics where phases total lethargy are often followed by episodes of surprising energy. I can second that exercise and the lack thereof can seriously affect your mental wellbeing. Watching sleep hygiene, excise and diet are important. Also check if you might be suffering from depression. Apart from that I have to say that I personally like this alternation and resting. If it does not feel awful for you maybe just accept this as your nature :)