God the Creator
I suspect that the short answer is that you can't convince yourself, and that no one can convince you.
Is it really more improbable that everything should just have 'happened' as it did, than that there is a Creator towards whom we are drawn by His love for us?
No one can 'prove' that creation was just a series of uncaused accidents; although it might have been. Equally, no one can 'prove' God did it; although no one can 'prove' that He did not.
Faith is what it is because we have not seen clearly. But we have received His Incarnate Word, and if we believe what He tells and shows us, then, having seen the Son, we can believe in the Father. To me, that is what it comes down to. We believe in a Triune God, and we are told that if we have seen the Son, we have seen the Father, the Creator of Heaven and Earth, and of all things seen and unseen.
In the Creed we declare our faith - that is mine - although I cannot prove it - no more than I can that He rose again on the third day, and ascended into Heaven, and is seated at the right hand of the Father, by whom all things were created.
No proof - but so many to the loving heart, which needs none; in the end, it is a mystery, and I believe what the Church has always taught - because, in the end, it is what my heart tells me is true.
In this is love, not that we loved God, but that He loved us and sent His Son to be the propitiation for our sins. (1 John 4:10)