tax credits nightmare due to increased income before renewal

We had a n income last year of 20774, estimated this year at 18500..updated in July due to becoming pregnant to 16000...have since today handing in notice at work, told I'm owed pay and holidays and getting other half wage slip I saw he had gone over my estimates for his wage....I had to inform them that we had a new estimate of 17700, up till this point our awards were based on 18500, is this the original or 16000+2500 disregard? I don't know...this was today...I'm so paranoid my payments are going to cease as now my award will be based on 17000+2500?right? Which means they have already paid me too much.???next Years income will be 14500 estimated as I've left work so - 5500 of the 17700+2300 oh wages increase for next year on top is 14500 ..so with 2500 this would be17000???

I'm not that bothered if I'm overpaid after renewal, I'm concerned about between now and the renewal...?anyone