Decreased movements

Never worried about this before... 38 weeks 6 days and I've been up 3 hours (lying in bed) waiting for movements and only had about 4 the first 2 hours so ate something sugary and had cold water and waited another hour and have only got one more small movement, don't know whether to ring hospital, don't want to waste their time as I know when I get there he probably won't stop moving! Any advice?