when i drive my car and turn heat on or deflost it blows cold air

I would change the thermostat it sounds to me like it's sticking

It could be anything from a thermostat and filter to a starter/alternator to a water pump. Start with fixing the thermostat and filter. It's about $10 tp $16 for the parts and easy to install. If that doesn't work you may have a bad starter/alternator which isn't giving enough power to make heat. And if it's not that it will be a bad water pump which isn't filtering the water properly and making the air come out cold! Just fixed this in my hope you figure it out (:

so if It is blowing cold air that means the thermostat is not working?

Best bet is the thermostat considering your heat gauge obviously isn't registering correctly

It doesn't necessarily mean that. It will blow out cold for all of the things I listed but thermostat is the cheapest and most common problem so it's where I started on my vehicle and it make it warmer but had to also get a water pump because it wasn't filtering the water which also makes the heat come out like ac

Most likely it's the thermostat

the water pump was just replaced last week so I should start with the thermostat first?

what is a thermostat and filter I didn't know that a thermostat has a filter?

Yes start with that. You purchase the thermostat and they tell you that you will also need the filter. The filter goes at the end of the black hose that connects to the engine and the other end of hose attaches to front part of car under hood(you are gonna need to ask the parts store for something to make filter stick) The thermostat doesn't go in the same place though all together it will cost you less than 20 for parts (at autozone) cost of labor I'm insure because I installed my own