Air carrier Flight Attendant reported an on going fume event during a two day trip with no resolution.

Narrative

We were to take Aircraft X to ZZZ from ZZZ1; the aircraft had a maintenance issue; the issue was said to be fixed in ZZZ1. In ZZZ1 when the engines were turned on my crew and I sensed and awful smell of vomit; we mentioned to the flight deck; the Captain said that was a normal smell since they were doing a fuel engine balance and oil check; so the smell was expected. During cruise to ZZZ the smell of vomit; mold and poop all combined persisted. We land in ZZZ; we tell the Captain about the smell and he said that was normal. Next day; we take the same aircraft; Aircraft X to ZZZ1 from ZZZ. When the engine started on the ground the smell in the cabin was just awful. The aircraft smelled dirty; like moldy; vomit; old cheese; poop what ever nasty smell you can think of; the aircraft smelled just like it. We again told the Captain and he said that was the smell that should be expected because the aircraft had the same problem. During cruising to ZZZ1; The smell became worse; it was so bad that my other crewmate FA4 (Flight Attendant) and I FA2 had to find a face mask to just bear the awful smell. I became nauseous; got a headache; and a burn and heavy sensation on my chest; all of the passengers that were sitting at the back of the airplane were complaining about the smell. Mind that myself being FA 2; I had to set up carts and prepare for a beverage service; consequently I was moving the most and since I was exercising; I believe that I was taking deeper breaths and the results was that I was mostly affected. However; since the Captain has been saying the whole time that the smell was expected; we seized to mentioned the problem. We landed at ZZZ1. The Captain doesn't say anything until I see two Mechanics onboard when we were deplaning. The Captain finally says that we had an oil leakage with a fume event during cruise and that he was having a hard time accessing his tablet to figure out the procedures. The First Officer complained the his throat was itchy; along with the other crew FA4. No one from the company showed up to ask if we were okay. I go directly to my manager to tell her what happens; she recommends that I go to the hospital. I get punished by the company with a sick call for going to the hospital because we still had two flights to work on. Three days later; I go to the hospital again with my joints hurting; headaches; and tiredness with inconclusive results with my white cells all out of whack; but not a sign of infection or virus. The flight deck along with the flight crew need extensive training about procedures and how to concretely recognize fume and odor event in the cabin. The flight deck also need extensive training and to listen to their cabin crew and to not put their personal needs before the cabin crew members and their passengers since the flight deck wear oxygen masks at all times. We; the cabin crew along with the paying passengers can occur health consequences with the dismissiveness; lack of procedural knowledge of the flight deck which in this case happened to us the cabin members and the passengers. I just hope that our passengers are okay and no adverse reaction occurred to their health since they have no knowledge of the event.