Hiya there Bridget
As Anne and Tricia have already mentioned, it does get worse before it gets better. It is very annoying and yes it can feel as if your under attack. Very often, it is normal to want to deny that those thoughts exsist in the first place, and trying as we do, which is normal to avoid them, ignore them, and to resist the temptation of paying them any attention only makes it worse. Often even with intrusive thoughts, the solution we adapt to cope is often the problem, meaning trying to avoid them and hope they will go away.
The idea of writing your intrusive thoughts in a diary, is to first acknowledge that they do exsist. Seeing your thoughts on paper, can be like gentle exposure of just having to read your thoughts that are disturbing. The more you read it, Like Anne suggested, the more your able to feel in time less anxious about them. It can be hard work, like a spoilt child seeking attention and when he/she does not get it, all hell breaks lose.
Or someone who did not like violent films like me, the more I watched them, the more I became desensitized to them and now I can watch those films without having any anxiety attached to them.
Now every time you read your diary and see those thoughts, your doing more good than you realise. Your taking charge of the situation, your slowly facing something that will have less fear attached to it. You will learn to accept small levels of stress and still feel safe. Each exposure, builds your confidence and you gain control over your thoughts, not the other way round. The process takes time but when you can see what you will achieve overall keep on going as they say.
if you need any help please send me a message and I will be happy to support you if need be.
Pam