Feel sleepy while doing mantra jaap?

Pranam Gurumaa Gurumaa I want to know when I do a kind of jap, after sometime I am feeling so much heavyness in my head and after mala I feel tired or dil me aata hai ki bus thoda so jaun. Aur uske bad neend ane lagti h, aisa kyu hota hai. Aur ubasi bhi bhut aati hai, kirpa iska karan bataaye. rachna jai gurudev गुरुमाँ जी :- रचना कारण क्या, इसमें तुम कुछ करना नहीं चाहते हो तुम्हें नींद आती है, सो जाया करो. जब नींद ही इतनी प्यारी है तो तुम को करना ही क्यों है जप. स्वामी बुआजी कहा करते हैं सोओ और सोते सोते मर जाओ. Go in sleep & die in sleep. You do not want to do your jap, so that is why you feel bored and out of boredom comes yawning & out of that boredom comes sleep. You really do not want to do the jap so don't fool yourself.