I want to put a gfci outlet in my bathroom where I have to tie into a light on a switch to get the power. There was a outlet previouly but was not gfci (house built in 1960) so I know that the circuit load would be fine. I am fine with the outlet only working with the switch on but is this going to cause an issue with the gfci. Also if this is fine I would have wires in and none out so it would be the end of the line, any issues with this.

I am not sure I picture this clearly but if there was a previous outlet you should be able to simply replace that outlet with a GFCI. How many wires are coming to the old outlet box? If you are tapping into this box to get power for a light there is no reason to wire it so the switch controls the outlet, it should be the other way around.

I took the bathroom fan and light that had their own switchs and tied it into another light. The outlet was ran off the original switches as there was a constant power coming through the switches from the ceiling. The lights still work as the constant coninues through the ceiling to the second celing light that has a vanity light that comes off it that I tied the fan and first light into, so I have one switch rather than three. So there is no constant power coming down out of the ceiling for the switch to go on to now as I took the first ceiling light off the constant power in the ceiling and just capped off the red wire (constant coming down through the switch to the outlet). And now the first ceiling light and fan run off the second ceiling lights power.

Back up several steps, please.

In the ceiling you have a constant source of power and a Neutral return to the panel.

Isolate that cable first. Then pigtail the Black to the outlet along with the Power to the switch (which may be a re-tasked white wire) to the supplies black conductor. Pigtail the white from the outlet to the White from the fixture to the Neutral from the feed source.

Now power is being fed to both the switch and the receptacle.

The Black from the switch (switched power) should come back to the light fixture and connect to the fixture's black.

PLEASE take care to note what wire is connected to where. Normally the Black / White paring from a cable can be used to feed and return from a switch.

Doing what you have suggested would require me to run a new wire from the ceiling down and I am trying to avoid doing that. By using the power from the light on the switch for the outlet. My basic question would be is there any reason to not have a gfci outlet run off a switch, will I having to rest the outlet every time the switch is turned off and on?

It should not matter. The GFCI is looking for an amperage imbalance. If it sees a problem, it shuts off the receptacle.

As to the switch arrangement, do you know whether the switches were three way switches?