Tax Credits Please Help.

I have just been on the phone to tax credits as I noticed my payment differed to what I was expecting.
He asked if I was receiving any state benefits I said no. I did receive carers allowance between jan-mar 2017 however I called to end this when I informed them of my new employment and childcare.
He said that although I wasn't as showing an income from carers allowance their was a marker ticked showing I was in receipt of it (incorrectly) for the whole of the last financial year and without this marker I probably will not have been entitled and therefore will probably have a £0 claim going forward and a very large overpayment.
Please can someone help me?

myself, husband and 3 children on the claim. eldest child in receipt of DLA higher care component and low rate mobility.

My details are as follows.

2016/2017

husband worked 37 hours and earned £32292

I worked 20 hours up until 31/12/16
01/01/17-27/03/17 claimed carers allowance (run on until 16/04/17)

income £12304
taxable social security £932

2017/2018

husband worked 37 hours and earned £30802
plus was made redundant and received £5800 pay (not redundancy)


I worked 22 hours earned £13023 plus run on of carers allowance approx. £130

Childcare 06/04-21/07- average costs £213pw

22/07-01/09 -160pw


02/09-29/11-£123pw


from 30th November no childcare costs.


I estimated £48000 income so am (was) expecting an overpayment.


This financial year 2018/19


estimated husband £34000

myself £13720


Childcare started on 18/04 £52 per week.


can someone tell me without the carer marker would we still be entitled last year and will we be entitled this year?


Agent said because of marker I was showed as incapacitated and therefore entitled to childcare and without it would have no entitlement.


I 100% called and told them about stop in childcare at the same time as informing them I would be starting employment and have call details.


Thank you I am soo worried.