What do you expect- you're new, you'll lose. I went through exactly the same thing when I was new. Just stick with it, practice combos(not single kicks!). Try to go from legs to hand techniques or the other way around. Don't try 25 punches in a row coz they'll just kick you REALLY hard. Don't throw loads of kicks coz they'll jab you in the head.
Apart from that I agree with Hoshinshool, oh, and do not use ankle weights!! They will **** up you knees and the tendens connecting the pattella to your thighs. Just doing kicks slowly into the air should improve your kicking power a great deal.