Need advice on what to say to HR of new company .

Background, I got laid off from an organisation and by god's grace I had a offer, which was not that good 10% decrement in salary, but me being a scared person joined the company. Now 1 month after I realised I can do much better and market seems to open up. What should I tell the HR in 2 scenarios. 1. I had already started Interviewing and haven't mentioned that I was layed off. What should I tell if I get selected? 2. If a opportunity comes to start Interviewing for seperate company, should I mention about ty current company or no? PS. The work in current organisation is not that good and it's a contractual role.