I went to the toilet and felt a lot of pressure felt something drop then there was no pressure could this be my mucus plug? It felt like my waters had gone but no fluid. Toilet had toilet paper down so couldn't see.

It could have been. How far along in your pregnancy are you? Usually the mucus plug has blood/tissue streaked through it so it would be a greyish mass with a red to red brown through it.

Losing the mucus plug could occur weeks before delivery, it could not happen at all. Have you talked to your doctor about the implications of this?

I'm 29 weeks with my 2nd, baby I went into labour at 29 weeks with my first.

If you think you lost your plug at 29 weeks, it would be best to contact your OB.

Urgently get a vaginal PH test and ultrasound to check the amount of amniotic fluid and for confirming if you have starteD leaking. If yes then do get dexamethason IM injection 2 with 12 hour gap for lung maturity of your baby.
Best of luck

Don't you mean dexamethasone 2 in 24 hours?

Its 2 to 4 doses of 6mg dexamethasone with 12 hour interval

In America we do it differently. 2 doses of 12mg of dexamethasone in a 24 hour period.