Of course, when you have rent to pay and no funds to pay it, any income becomes important income. But, it is very risky to need outstanding payments from freelance work to pay current bills. Even the most reliable client who always pays on time does so right up until the moment they don't. Upwork has some protections but you have to follow carefully defined rules to earn those protections. And, if the client is committing fraud, there may be no protection.
You agreed to do a lot of work for a small fee. I did that when I was first getting started here, too. But you should understand two things when using this strategy:
1. Clients who don't think your time has value will behave according to that belief--they will not value your time
2. Every minute spent trying to please a client who doesn't value your time is a minute not spent finding and working for a client who will--the more greedy the client, the higher the opportunity cost