Because it shows "You have no transactions", there is a possibility you have not lost your coins. Instead, it's possible that you have lost track of your account, and once you find the correct account, it will still have the coins in it.
This is an example of the mathematical derivation path used in crypto wallets:
Mnemonic 0 > Private Key 0 > Public Key 0 > Account Address 00 > Contract Address 000
> Contract Address 001
> Contract Address 002
> Contract Address 003
> Contract Address 004
Mnemonic 0 > Private Key 1 > Public Key 1 > Account Address 01 > Contract Address 010
> Contract Address 011
> Contract Address 012
> Contract Address 013
> Contract Address 014
Mnemonic 0 > Private Key 2 > Public Key 2 > Account Address 02 > ...
Mnemonic 0 > Private Key 3 > Public Key 3 > Account Address 03 > ...
Mnemonic 0 > Private Key 4 > Public Key 4 > Account Address 04 > ...
The first part
Mnemonic > Private Key is optional, but used in Metamask and all wallets where you have "secret recovery phrases" i.e. mnemonics. You can also start off with a private key, skipping the first step.
These steps are "deterministic", meaning if you start with the same mnemonic (e.g. 12 word recovery phrase) you end up calculating the same private keys, from which you calculate the same publics key, and so on, every time. There is no randomness or variance.
From this mnemonic + a counter, you can calculate many private keys. The counter is called a "nonce" and the mnemonic with a nonce of "0" gives you your first address. This is probably what address you used in metamask.
The mnemonic when used with the next nonce of "1" gives you another Account Address, and so on. (The same process is used to derive multiple contract addresses from one account address.)
My point is, all these account addresses are derived from the same Secret Recovery Phrase, in sequence. They are all your accounts, and they all come from the same Recovery Phrase.
And I suspect metamask is just not looking at the correct nonce (sequence number) i.e. not the correct account.
If you know your original account address (which looks like a 0x followed by a 40 character hex string; possibly you would have shared this account address in order to receive funds) then just pop over to blockscan.com where you can publicly see which chains this address is on, and look at the account balance and transactions on the etherscan website (assuming you used this on ethereum).
If you can see the previous transaction amounts and dates and they match up with what you remember, and yet now the current balance is zero, then yes you lost the funds. But you can also see which account address the funds have been sent to and when.
More importantly, if you can't see your previous transactions directly on the blockchain via a blockchain explorer (like etherscan.io for ethereum), then it's clear that you have the wrong account address. The blockchain is immutable and past transactions cannot disappear.
Re-setup Metamask by removing the account, and re-adding it using the original 12-word recovery phrase. The first account is created with nonce 0. Keep creating additional accounts (Metamask will use the same private key and automatically increment the nonce, to 1, 2, 3 and so on) till you hit the correct account with balance in it.
Here is the related answer from the metamask site: https://metamask.zendesk.com/hc/en-us/articles/360015489271-How-to-add-missing-accounts-after-restoring-with-Secret-Recovery-Phrase
There are online services to recover missing crypto from metamask wallet which can identify these accounts and display on-chain balances to identify the right accounts but it's better if you can download and run such software locally. Also immediately move the funds to another account after recovery.