Super Ammonia Spikes

Question
I have had a 5 gallon fresh water tank for 1 week and have had so many problems I am honestly thinking of just dumping the whole idea.
I started off with two gold fish (from the local fair) and added three guppies. I purchased my tank on Monday, added my fish on Tuesday. I purchased a bacteria supplement, Live NH3 monitor and a starter tank (which came with a filter and a sample of water conditioner).
On Thursday one of my guppies died. I looked at the monitor and it was at a caution level so I did a partial water change, re-conditioned the water added bacteria supplement. No change.
Saturday I did a bigger water change, re-conditioning and supplement again... then changed the Live NH3 cartridge as I did not see a change and figured it was bad.
The new cartridge was fine for about 6-8 hours then went to caution. Spoke to my brother in law (a long time fish owner) and he said let it be... that I may have had too many fish in it.
On Monday one of the gold fishes was dead and the reader was still at caution. Yesterday (Tuesday) it went to stress, i left it (as per my brother in law's instructions) and nothing... today (Wednesday) it is at danger. I don't know what is causing it, i added more of the supplement and no change. Could it be the heat... It is very, very hot in my apartment though i have not tested the water i imagine it is in the low 80's temperature wise.
What am I doing wrong? the water looks super clean and there's not extra food as i only give them a few flakes at a time and they seem to be eating them all.
HELP!

Answer
Well, to start you were overstocked with four fish to one 5 gallon. Also, I advise against getting the extra bacterial supplements as they often just add extra waste to the tank rather than be good. Get a normal de-clorinator with no added bacteria or anything, just a de-clorinator. Also, check your filter cartridge, it prob needs to be changed. Also, you filter may not be good enough for the tank, you may have to replace it. Plus, goldfish are super dirty fish, in my opinion not for beginners, and are contributing to the ammonia. Finally, even though the tank is going through a cycling time, if you leave the ammonia at a high level the fish will become stressed and possibly die. You will need to do a large water change every day until the ammonia is down to the bareable level. Also, do a good cleaning, especially the gravel. Other than these steps you just need to keep it maintained and watch it for a while to make sure during its cycle it doesnt get too high again. Let me know if you need more help. I hope everything balances itself.