Can I get outbid while under contract? Options?

[YiBing T.]

Hello BP Community, 

I'd like to get your opinion on a situation. I found a property that was marketed for sale while I was on a home inspection of another property just a few doors down the street. I contacted the selling agent personally and started working on the contract. Long story short, after a few backs and forth, and a long delay from the seller's agent (due to health issues), we finally got the contract signed. Just about 30 minutes after I send back the ratified contract to the seller agent, the seller agent emailed me back and said they are receiving multiple offers and ask me to send in the best. 

My question is since I already have a ratified contract, could I still be outbid?

What are my options with the situation like this? 

If I decide to settle with the seller to void the contract we are in now, what would be a fair dollar value to settle (we prefer to settle without any legal actions)?

Are there anything else I should be aware of? Thank you.