I only started investing 2 years ago: Is it possible for SnP500 and NASDAQ 100 to collapse?

I am fine with holding long term, but seeing 20% loss in like 2 months and being down 7000 dollar when I am trying to save up to buy a home doesn't feel good

Is it possible for me to lose all my money?

I am fine with waiting, I just want to know if I am pumping money into an incinerator whenever I buy the dips with whatever savings I have