Louiselouie, youre putting too much pressure on yourself. (I blame MN 
This place has been quite a lively political hotbed well for ever.
Things to pick up from that, are, just how politics does indeed impact peoples day to day lives. However, I can assure you, there are very possibly, no phd educated politicians spouting the 'real truth' behind politics on here. What you have is a total mixed bag of highly opinionated women (me included).
Our political system is flawed in many areas. For example, youre right, what if you vote for a manifesto promise from one party, for them to win, and then not carry out that promise?
Its happened alot. It will continue happening. (If anyone now derails this post to make political gain, Ill be mightily non-plussed!)
But that said, all we can do as an electorate is vote on what we believe the promises are, and then make a bug fuss to demand they deliver their promise. What generally happens when a party doesnt deliver is, they tend to get kicked out at the next election. Credibility down the drain....yet again.
Politics is a huge area, because it covers every aspect of our daily lives. How we live. Our children. etc But dont be daunted by that. The whole point is, the man on the street, no matter how lowly, ill educated, has a right to be heard, at the ballot box. His experience of living in the UK today, is no less important than some phd professor from Oxford. Indeed, Ive said this on other threads, Id argue that the man on the street is far better qualified to vote, than the phd professor in Oxford.
Dont be daunted by it. Your single vote will have to be one of many to impact the result. That in itself should build confidence that thousands felt the same way you did. That actually still applies on the losing side too. Or even, if you want to vote for a totally new independant candidate whose just starting out, who seems to reflect how you feel about things, vote for him/her. This time around he may get 200 votes, but encouraged, next time he may get 20,000. Or 200,000. This is how change happens in small steps, one person says, you know, Im sure we can do this better? This is how Macron, came from nowhere in France, and today is President from his first election.
If theres really no one you like, or issues you feel aligned to, draw a willy!