Take it slow. Start practicing one hour per day and increase the time period. Take little breaks in between. The main important thing here is focus and if you are not focused, then it's useless to draw some random lines. Hope this helps. Happy drawing.
Whenever I lose inspiration I just take a break for a few days. I'm online a lot, and I usually find some piece of art or a photo that slams my creativity into overdrive in no time at all. Try to think of some artists or influences that've inspired you in the past!