Hello Monic, welcome aboard Filipina Roses

You might want to consider making an application as unmarried partner

To be eligible you need to satisfy the following:-

- You must prove that you and your partner are 18 or over and in a genuine relationship.
- Have been living together in a relationship for a minimum of 2 years and provide full documentary evidence of this
- Prove that any previous relationships you or your partner had are permanently broken down.
- Have suitable accommodation available for you, your partner and child
- Satisfy the UKVI English language requirements
- Have a valid TB test certificate
- Sponsor to satisfy the UKVI financial requirement of minimum £18,600 per year.

I guess your child already has a British Passport ?

If there are any problems to meet all requirements at this time then really you have no other option but application for a max 6 months visit visa. Do be aware that this may not be granted but at least the cost is low and the decision is quick.

Take a look here and follow all relevant links:-

https://www.gov.uk/join-family-in-uk/overview