There is a tendency among HVAC users to start to panic if their unit does not provide as much cooling or warmth as they desire, but there is a pretty good chance that many of the issues you are facing are basic to say the least. If your HVAC unit is pushing out air in bursts rather than with a consistent flow, this might be caused by clogged air filters which can be cleaned up easily with the use of a small pressure washing device or a toothbrush.
The truth of the situation is that mistakes made during air conditioning installation can also result in poor performance of your HVAC, and you just need to adjust the settings to help it function optimally for a good long while. That said, there are definitely a few issues here or there that might indicate that your HVAC is actually broken. For example, if your HVAC unit is freezing over even though it has enough coolant, this means that there is a leak in the coolant pipe that needs to be wrapped up.
Another thing that can tell you that your HVAC is broken is if the air is unobstructed but it is at room temperature. Excessively loud noises from your HVAC are also a sign that it needs to be repaired, and the fact of the matter is that you should get this repair done as soon as you can lest the problem become worse. You should also take note of the humidity levels in your room. Cooling and warming are the basic functions that your HVAC is supposed to provide, and they are useless without humidity control.